As described, if you select "Auto-Split Stacks" in a factory, the factory "forgets" that choice and reverts back to filling single stacks from left to right.

All relevant mod version information is in the attached forced crash report.

https://pastebin.com/jvS6RVR8

EDIT - I noticed this with the Furnace and Compressor factories, I have not built other ones or tested them.

EDIT - this is going to be hard, because it does not happen all of the time. No idea what is triggering it. Sometimes it works, sometimes it does not. No rhyme or reason to it.

I am going to close this. I am not sure what exactly is going on, but now it is working. If it comes up again, I will reopen this. I did nothing (other than restart, again) and it is working.