Having a similar issue, only I noticed that when this happens, the infant often has an action queued, Sleep with Pet. It seems that the parents are wanting to take the infant OUT of bed so they can sleep on the floor with the cat/dog. It got so bad once I locked the parents out of their baby's room.
I believe I have discovered the ultimate workaround:
DELETE YOUR CRIBS.
let infant sleep in a pile of horse manure: WELL CARED FOR VERY HAPPY FALL ASLEEP IMMEDIATELY
put infant in upgraded crib: CRY CRY GET PICKED UP AND PUT DOWN 200 TIMES CRY GET TAKEN OUT OF CRIB AND PUT BACK IN IN REPEATING LOOP FOR ALL ETERNITY ENERGY IS DEEPLY RED FOREVER
Seriously, only using the crib as a last resort and otherwise just leaving your infant sleeping on the dirty floor works much better. Also, pause and immediately queue up tasks for every adult in the household if you do use the crib, and lock them out of the nursery if necessary.
(Delete your high chair, too. I still have PTSD from the high chair with toddlers.)
I've also been having this problem. My sim puts the infant in the crib and then autonomously takes it out again unless I manage to queue up another interaction first. Looks like this is same issue reported here, although I don't think it's mod related: https://answers.ea.com/t5/Game-and-Mod-CC-Issues/Struggling-to-put-infant-in-crib/td-p/12389370/highlight/true
In general, interacting with infants is glitchy. Sims will autonomously undo the previous action concerning an infant (e.g., taking it out of the high chair right after putting them in it) unless you queue up something else first. They will also often refuse to pick up the infant (interaction disappears from queue or they act like something is blocking the way when there's nothing there). And they're constantly dropping queued actions in order to "check infant."
