Why did this question allow one answer after hold but not mine?

Question

I was in the middle of writing an answer to this question when it was held for being a duplicate. (This meta is not about the duplicate status, just that it was and still is held as of this meta.)

Once the question was held, the SE interface refused to let me post the answer I was already composing. Yet several minutes after the question was held somebody else's answer appeared. I've checked the time stamps: that answer appeared about 20 minutes after the question was held.

I'm curious why/how this happened. I understand that sometimes the site is permissive/flexible regarding in-progress content (like editing a comment after the time limit has passed), but why was I forbidden to post an answer within seconds after the question was held even though another user was allowed to post an answer many minutes later?

Answer 1

It's generally a question of client- vs. server-side restriction of the post during that period between closure and your page's refresh. But I'm not much of a computer guy, so you should definitely read the real explanation on meta.SE for better information =)

Answer 2

I'm the answerer on that question.

I am using the android app for Stackexchange, and was writing the answer before it got closed. I'm always slower to finish an answer in the app than in desktop site, so it took a while, then it got submitted after the question got on-hold.

I recall there's a post somewhere explaining there is a window of accepting answers, but in desktop website there is a mechanism that disable submit button if the question got on-hold while you writing your answer. This is not the case with the android app, so you can still submit your answer even after the question got on-hold.