Apparently the variable
bpy.data.objects[rig].data.bones[bone].bbone_in / bbone_out were changed to bbone_easein and bbone_easeout.
Rigify references the previous names but since they're non-existent, it breaks as error.
It's referenced in multiple files, but the first error call is in generate.py line 182
I opened all the .py files in my folder and search/replaced all bbone_in/bbone_out with bbone_easein/bbone_easeout.
It's working now for me: