"Someone edited the issue at the same time" is regularly seen despite that being a filthy lie

This is a very common problem, as seen from chat:

Personally I've seen it happen just about every time I edit an issue description inline, on issues that I know I'm the only one editing.

I can't imagine that this issue won't be a duplicate of a pre-existing one, but multiple requests for an issue for this have gone unnoticed, so here we are.

Edited by Stan Hu