The way the game is currently set up, they need to go to "Analyze PC Pregnancy" from Personal Affairs to reserve a specific fetus.
Analyze Preg is not available in this save, because they don't have the pregnancy monitoring upgrade. They can't get the upgrade yet either, because their rep is too low.
Everything working as intended, as far as I can tell.
Didn't want to start a new issue - not sure if this will be seen: Is there an explanation you're unable to reserve incubators for PC children without analyzing them? 10000 rep is required to unlock that function while you can reserve pods for regular children at no rep cost. Seems nonsensical to me.
If you can't change that back to how it was before: Are there repercussions to enabling cheats in a save?
Unless I've overlooked something I've not been able to reserve a spot even though none of the pods had a reservation. In the options Mothers|You|Tanks|Settings I'd expect to be able to reserve something in 'You' but all I see is 'You're 39 weekspregnant quintuplets [sic]. You have available aging tanks.' and nothing to click on. Nothing in 'Personal Affairs' either.
I can't do anything in the birthing screen either, obviously.