First off, thanks for all the work you put into this -- been following the mod for ages and it's a ton of fun.
I noticed two things:
1) fresh install of game and mod and a rush to try dog impregnation on a halfkin resulted in an error on globals line 2133. Looking back, it seems that line 2097,
if father_id != null && father_id != '-1' :
doesn't actually catch unique fathers. In my save file the semen deposits (all from random dogs) all have ids not equal to -1, and are only set to -1 in the ELSE side of the above if statement. I made a dummy statement to pass into the "else", loaded the save file, and fertilization went through with no issues at all.
2) I then got the following:
SCRIPT ERROR: dailyPregnancy: Invalid get index 'back' (on base: 'Array'). Did you mean '.back()' or funcref(obj, "back") ? At: user://mods/AricsExpansion/scripts/aricsexpansion/expansion.gd:1771
I made the suggested change from back to back() in the file and it ran fine. Progressed time for a few weeks after these changes and everything else seems to be working.
Looking forward to messing with the rest of the update.