With Manage Household, I transferred the infant Sim into the household of someone not currently in a household (since this is a new bug, I didn't know what to expect). I then moved the two Sims to an apartment.
The infant floated down as normal. Before the bug, it was normal to be asked by the game if the infant's going to be as is or uses the DNA of the new family, but that option did not appear.
When I had the cursor over the infant, with the adult Sim being controlled, there was an option 'Ask to be introduced by..." (which, when the mouse is over this option, it says "You haven't met the caregivers of this infant. Hey where are they anyways?") and an option to adopt the infant.
I clicked on the adopt button, and it still show the 'Ask to be introduced by...' option, I'm able to choose the back carrier, feeding preferences and read the infant a book.