Layershift caused by underruns?

Nxt-1

I have been experiencing a consistent layershift at the same height in a print. The layershift consistenly happens at the same height, around ~30.78mm. In the M122 logs I also noticed under in two of the categories, are these related?

Setup: Delta printer with a Duet3 6HC in SBC mode with a Jetson Nano (rrf 3.3).
Slicer: S3D
G-Code: 4thAxisMotorBracket2.gcode
Config.g:

; Configuration file for Deltex

; ===================== GENERAL SETTINGS =====================
M111 S0                             													; Debug off
;M550 PDeltex - V6																		; Machine name and Netbios name
M555 P1                                   												; Repetier Output
M575 P1 B57600 S1                          												; PanelDue Comm Setup
M586 P1 S0																				; Disable FTP
M586 P2 S0																				; Disable Telnet
M912 P0 S-12.30																			; Set temperature offset for MCU

; ===================== MOVEMENT SETTINGS ====================
G21                                 													; Set Units to Millimeters
G90                            															; Set to Absolute Positioning
M83                                	 													; Set extruder to relative mode

;Drives
M569 P2 S0																				; Drive 2 (X) goes backwards
M569 P1 S0																				; Drive 1 (Y) goes backwards
M569 P0 S0																				; Drive 0 (Z) goes backwards
M569 P3 S1																				; Drive 4 (E) goes forwards
M584 X0.2 Y0.1 Z0.0 E0.3																; Assign drives to axis

;Mechanicals
M669 K3																					; Set kinematics type to 3 (lin delta)
M665 L501.300:501.300:501.300 R230.970 H771.051 B200.0 X0.000 Y0.000 Z0.000				; L-Diagonal rod length, R-delta radius, B-printable radius, H-homed height
M666 X0 Y0 Z0 A0 B0																		; Endstop adjustments
M579 X1.005 Y1.005 Z1.005																; Cartesian axis scaling

;Endstops
M574 X2 S1 P"0.io2.in"                            										; configure microswitch endstop for high end on X via pin xstop
M574 Y2 S1 P"0.io1.in"                            										; configure microswitch endstop for high end on Y via pin ystop
M574 Z2 S1 P"0.io0.in"                            										; configure microswitch endstop for high end on Z via pin e0stop

;Speeds etc
M350 X16 Y16 Z16 E16 I1    																; Set 16x microstepping with interpolation
M92 X160 Y160 Z160 E414																	; Set steps/mm
M906 X2400 Y2400 Z2400 E750 I60															; Set motor currents (mA) and increase idle current to 60%
M98 P"0:/macros/Commands/set_acceleration_default"										; Accelerations (mm/s^2)
M203 X10000 Y10000 Z10000 E10000														; Maximum speeds (mm/min)
M98 P"0:/macros/Commands/set_jerk_default"												; Maximum instant speed changes (mm/min)

; ================ HEATING AND COOLING SETTINGS ==============
; Bed
M308 S0 P"0.temp1" Y"thermistor" A"Bed" T100000 B3950									; Bed temperature sensor parameters
M950 H0 C"0.out7" T0 Q10																; Connect bed heater output and proper sensor, set switching frequency to 10Hz
M307 H0 R0.768 C475.700:475.700 D5.20 S1.00 B0 I0										; Set bed heating process parameters and use PID
M140 H0																					; Map heated bed to heater 0
M143 H0 S150 A1																			; Set maximum bed temperature to 190 -> switch off permanently

;Hotend
M308 S1 P"0.temp0" Y"thermistor" A"Hotend" T100000 B4725 C7.060000e-8					; Hotend temperature sensor parameters
M950 H1 C"0.out1" T1																	; Connect hotend heater output and proper sensor
M307 H1 R1.582 C305.900:291.600 D6.73 S1.00 B0 I0										; Set hotend heating process parameters and use PID
M570 H1 T5 S4320																		; Configure heater fault detection (+/- 5°). Cancel the print if the fault is not cleared after 4320 minutes (3 days).

;Water
;M308 S2 P"e1temp" Y"thermistor" A"Water" T9577 B3306									; Water temperature sensor parameters

; Fans
M950 F0 C"0.out2" Q2000
M106 P0 L0 X0.7 H-1 C"Compressor"
M950 F1 C"!0.out4+out4.tach" Q25000
M106 P1 L0.0 X1.0 H-1 C"Duet"
M950 F2 C"!0.out5+out5.tach" Q25000
M106 P2 L0.0 X1.0 H-1 C"Pump"
M106 P2 S1																				; Turn the pump to max rpm

; ====================== TOOL SETTINGS =======================
M563 P0 D0 H1 S"Hotend"              													; Define hotend tool
G10 P0 S0 R0                        													; Set tool 0 operating and standby temperatures
M207 S0	R0 F3000 T1200 Z0																; Set default retraction settings

; =================== CALIBRATION SETTINGS ===================
M558 P8 F1000 H5 R0.5 T10000 A10 S0.03 C"0.io3.in+0.io3.out"							; Z Probe type 8, input 0, invert no, dive height 5.0mm, probe speed 50000mm/min, travel speed 10000mm/min, recovery time 0.40 sec, heaters normal, max taps 10, max diff 0.03
;M672 S105:100:155																		; Command to set sensitivity
;M672 S105:75:180
G31 X0 Y0 Z-0.10 P100  		        													; Set the zprobe height and threshold (more negative values translate into a higher nozzle)
M557 R190 P10																			; Define probing mesh grid

T0																						; Select hot end
M501																					; Load settings from config-override.g

M122 output:

M122
=== Diagnostics ===
RepRapFirmware for Duet 3 MB6HC version 3.3 (2021-06-15 21:45:47) running on Duet 3 MB6HC v1.01 or later (SBC mode)
Board ID: 08DJM-9P63L-DJMSS-6JKD0-3S06T-9AF79
Used output buffers: 1 of 40 (15 max)
=== RTOS ===
Static ram: 150904
Dynamic ram: 60740 of which 0 recycled
Never used RAM 139692, free system stack 127 words
Tasks: SBC(ready,100.4%,314) HEAT(notifyWait,4.3%,325) Move(notifyWait,10.5%,246) CanReceiv(notifyWait,0.0%,944) CanSender(notifyWait,0.0%,358) CanClock(delaying,2.4%,333) TMC(notifyWait,7.9%,59) MAIN(running,105.2%,186) IDLE(ready,0.1%,29), total 230.9%
Owned mutexes: HTTP(MAIN)
=== Platform ===
Last reset 284:21:55 ago, cause: power up
Last software reset at 2022-02-03 16:52, reason: User, none spinning, available RAM 139908, slot 2
Software reset code 0x0012 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x0044a000 BFAR 0x00000000 SP 0x00000000 Task SBC Freestk 0 n/a
Error status: 0x00
Aux0 errors 0,0,37
Step timer max interval 300
MCU temperature: min 30.3, current 39.6, max 47.4
Supply voltage: min 31.9, current 32.1, max 32.3, under voltage events: 0, over voltage events: 0, power good: yes
12V rail voltage: min 12.2, current 12.2, max 12.3, under voltage events: 0
Heap OK, handles allocated/used 99/0, heap memory allocated/used/recyclable 2048/700/700, gc cycles 1
Driver 0: position 98609, standstill, reads 63189, writes 105 timeouts 0, SG min/max 0/1023
Driver 1: position 100879, standstill, reads 63189, writes 105 timeouts 0, SG min/max 0/1023
Driver 2: position 102640, standstill, reads 63189, writes 105 timeouts 0, SG min/max 0/1023
Driver 3: position 0, standstill, reads 63221, writes 73 timeouts 0, SG min/max 0/1023
Driver 4: position 0, standstill, reads 63284, writes 11 timeouts 0, SG min/max 0/0
Driver 5: position 0, standstill, reads 63284, writes 11 timeouts 0, SG min/max 0/0
Date/time: 2022-02-20 17:14:30
Slowest loop: 195.60ms; fastest: 0.03ms
=== Storage ===
Free file entries: 10
SD card 0 not detected, interface speed: 37.5MBytes/sec
SD card longest read time 0.0ms, write time 0.0ms, max retries 0
=== Move ===
DMs created 125, maxWait 596714444ms, bed compensation in use: none, comp offset 0.000
=== MainDDARing ===
Scheduled moves 69002, completed moves 69002, hiccups 0, stepErrors 0, LaErrors 0, Underruns [2344, 0, 21], CDDA state -1
=== AuxDDARing ===
Scheduled moves 0, completed moves 0, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 0], CDDA state -1
=== Heat ===
Bed heaters = 0 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1, chamberHeaters = -1 -1 -1 -1
Heater 0 is on, I-accum = 0.0
=== GCodes ===
Segments left: 0
Movement lock held by null
HTTP* is doing "M122" in state(s) 0
Telnet is idle in state(s) 0
File* is idle in state(s) 0
USB is idle in state(s) 0
Aux is assembling a command in state(s) 0
Trigger* is idle in state(s) 0
Queue* is idle in state(s) 0
LCD is idle in state(s) 0
SBC is idle in state(s) 0
Daemon is idle in state(s) 0
Aux2 is idle in state(s) 0
Autopause is idle in state(s) 0
Code queue is empty.
=== CAN ===
Messages queued 9213757, received 0, lost 0, longest wait 0ms for reply type 0, peak Tx sync delay 0, free buffers 49 (min 49), ts 5118577/0/0
Tx timeouts 0,433,5118576,0,0,4094745 last cancelled message type 30 dest 127

=== SBC interface ===
State: 4, failed transfers: 2, checksum errors: 0
Last transfer: 1ms ago
RX/TX seq numbers: 57047/57047
SPI underruns 0, overruns 0
Disconnects: 0, timeouts: 0, IAP RAM available 0x2c83c
Buffer RX/TX: 0/0-0
=== Duet Control Server ===
Duet Control Server v3.3.0
Code buffer space: 4096
Configured SPI speed: 8000000Hz
Full transfers per second: 36.05, max wait times: 35.0ms/0.0ms
Codes per second: 0.92
Maximum length of RX/TX data transfers: 5384/1684

Phaedrux

Nothing mechanical potentially?

Nxt-1

Hi @phaedrux , I missed your reply. No not mechanical as I did several prints before and many more since, without as much as a hint of a layershift. At the same time I was not able to reproduce the underrun values while printing that file. The layershift did occur again with that file but I have a part now that is 'good enough' so haven't bothered with it to be completely honest.