How can someone answer a question after it is put on hold?

Question

This question is put on-hold with me as the last voter. At that time no one posted an answer and I'm sure because I put a comment after that.

However, somehow there's an answer after it was put on-hold. I confirmed the time it was closed via revision history and the time the answer was posted. It was a 1-minute gap.

I've never encountered this, as in my experience someone who is writing an answer while the question is closed will get a notification bar stating the closed status, and even further receive an error when trying to post that answer.

Is this a bug?

Answer 1

If you look at this question on Meta.SE, you'll see that yes, it was because it was posted from mobile.

When a question is closed (or put on hold), there's a client side thingamajiggy that disables the post answer button. However, quoting @TimStone on his answer to the above linked question:

For users answering from a mobile device, there's no client-side restriction in place to begin with, so this situation is presumably even easier to create when using the mobile version of the site.

Answer 2

Just a guess, but I did a rapid edit immediately after posting which may have effected the time stamp.

Also I posted from mobile, so it may be a mobile issue... You don't get the same close and edit notices when you're writing an answer on a mobile device.