@dc42 Hmm, I wish I remebered which tool I printed the prints with issue with....
Two of my tools use extruders on a slave Mini 5 board while the other two tools are connected to the 6HC... Maybe it has to do with the extruders not being on the main board?
I just went back to older builds (specifically the one where you fixed the Mini 5 Slave OoM error) and I can see hints of the issue appearing again when I use one of the tools with an extruder on the Mini 5. It's not as bad as before, but maybe other things play a role.
I'll keep experimenting...