Collapsed after editSomeone might have reported your answer or mods found either offensive or irrelevant content. They even collapse 1 word or short answers. Quora generally sends a DM with the reason for collapsing the answer. Check if you got a message from them.
They don't collapse answers for edit. Even I've edited 2 answers today and nothing happened. Appeal the collapsed answer for review.Collapsed after edit
the same to meafter 1 days i saw my answer.