I am also having this issue. My toddler will take the plate and sit with it on their lap without moving and then get up and put it away - the entire time their hunger declines.
They do the same thing in the high chair.
I've also noticed that when my toddler is stacking blocks they sit next to the blocks (not even facing them) and don't move. but their skill does go up. So while the lack of motions seems related the fact that their hunger does not increase with the food is not. And TBH I have to keep cheating the need.
This only started happening to me after I switched from Origin to the EA app on my Mac.