Toddler/Infants/Child body and face distortions

Same here, although not to this extent

I'm having this same issue. Not as badly as some, but it is noticeable. These are all sim children and a toddler that were born in game. They have never been aged up in CAS. The child boy seems relatively normal as far as I can tell, but the child girl has noticeably gained weight in her stomach and rear. Having her use a slimming potion keeps her torso the same but gave her skinny arms and legs. My toddler seems to have a different shaped body too, but I lack previous screenshots to show exactly how. He looks older? A longer torso I think. I think my infants are ok but that family is so chaotic with 2 infants, a toddler, 2 children and a dog I didn't look at their faces closely! Interestingly they seemed to change gradually? I swear the girl looked normal at first but got fatter. I quit without saving so cannot provide a save file at the moment. 

EDIT: I have a couple of crafting mods and some custom farm animals, but all other cc is build/buy stuff.

Yess i've the same glitch, kids look like pregnant! 

i think i'm having a similar problem, only my sim's child son has the body of a grown man. muscled up like he's been in the gym all 10 years of his life. my sim's toddler son is also visibly taller and his face has changed quite a bit, almost to the point where he looks like an adult in the face, but with a toddler nose...? idk i just logged into my game and logged right back out after seeing all of that lol.

I just did similar testing pulling Maxis households from the Gallery that have children in them and saw the same results.

The newest Maxis household on the Gallery (Hawley) has this problem with the child girl having a deformed belly. Other Maxis households with children have similar issues.

This is very easily reproducible.