I was able to reproduce this on launchpad.dev doing the following
1. http://launchpad.dev/firefox/+bug/1/+editstatus
2. Enter any comment in 'Comment on this change'
3. Re-assign the bug to a non-existent person: 'fooobarino'
4. That will trigger a form error and the comment is gone.
I'm not sure if this is the issue Fabio originally reported.
I was able to reproduce this on launchpad.dev doing the following launchpad. dev/firefox/ +bug/1/ +editstatus
1. http://
2. Enter any comment in 'Comment on this change'
3. Re-assign the bug to a non-existent person: 'fooobarino'
4. That will trigger a form error and the comment is gone.
I'm not sure if this is the issue Fabio originally reported.