I've run into the error as well. I suspect it's a recent change in Bob's that's causing this for me. Here's the traceback:
72.033 Mods to disable:Failed to load mods: __mini-machines__/func.lua:776: attempt to index field 'hr_version' (a nil value)
stack traceback:
__mini-machines__/func.lua:776: in function 'fixEntity'
__mini-machines__/func.lua:342: in function 'reduce'
__mini-machines__/func.lua:65: in function 'miniaturize'
__mini-machines__/data-final-fixes.lua:71: in main chunk
Which at the top-level points to (in data-final-fixes.lua):
if mini.chemplant then
if mini.bobs.chemplant then
miniaturize("chemical-plant","mini-chemplant",4) -- this line
Commenting out the miniaturize line worked as a workaround for me, while sacrificing mini-chemplants, ofc.