Description of problem: How to reproduce: 1) Set up a large number of bugs in 'change multiple bugs at once' (such as a few hundred) 2) Set them to only change one field 3) Hit submit 4) Eventually, you'll get a proxy error. You won't get a result page, but your change is still running in the background 5) Have someone else change unrelated fields in some of these bugs (assignee, status, resolution, etc.) before your change is run on the bug 6) Your change then resets whatever fields the other person has changed back to their state when you started your submission, without warning. It's essentially the situation that required the mid-air collision warning, except it blindly overwrites things with no warning. And it's doubly problematic in that the situations where you'd want to use the 'change multiple bugs' page is where you're more likely to exacerbate it. Version-Release number of selected component (if applicable): bz-current
This is a known issue from upstream Bugzilla.