Did anyone find any way of dealing with this yet ?
It happened to me yesterday for the first time.
I noticed that both the dad and the mom had both given milk to the baby in very quick succession one after the other, but I don’t know if it’s related or if it has nothing to do with it.
I have the same issue. What is super frustrating is that I am dealing with a bug where I can’t feed my toddlers in the highchair, so bottle feeding is the only option I have. 
Just like @mialuce66 said, I think this moodlet is related to how frequently in a short amount of time the toddler gets fed. IMHO this is intended to indicate that the parent chose the “wrong” interaction when the toddler was crying.
feeds toddler → a few in-game minutes pass → toddler starts crying → other zoi reacts by feeding them again → vomiting moddlet due to overfeeding