Can't force pregnant women to work [duplicate]

Basically, when a dweller becomes pregnant, I can usually send them back to their work stations from the Residence room. For some reason, that doesn't apply to all of them, since sometimes they get stuck in said Residence room, i.e. I'm not able to select them and drag them to a different room as the green silhouette (that appears when you drag dwellers around) disappears as soon as I drag it (but is still there if I just hold my finger over said pregnant dweller). What gives?

Solution 1:

It sometimes happens. The two main workarounds are:

• Exit to the main menu and re-enter the vault
• Force them to leave the room by assigning 2/4/6 other people to the room. This "resets" the pregnant woman (supposedly, I never bothered, since the first option seems easier)