Citizens stuck when stockpile settings changed while they are storing items

Still in R210; I think it’s to do with updated planning by the AI, or updated pathing, or some such, as the first time I noticed it (two citizens at 45:50—one moves again at 46:46; the other at 50:00) they were carrying items, and the second time (1:00:11) was after the guy just finished building a ladder.