I could not reproduce those, but I have only about 10 MB of data in my databases, so if you can try dumps on large databases and find something reproducible, it would certainly help.
I have access to databases with 1.000.000+ records so I'll try to make some tests over the next couple of days to see if I can find a pattern or even reproduce the bug.
I've been testing with the very little information mentioned in the assigned bug #448223 - and I'm not sure that I with the little available information thats reported can reproduce the bug - so if any on this list can tell more about the bug or even reproduce it - I'll be greatfull to hear any information, because I don't think that I can reproduce it at all.
(Marc - you opened the bug in the tracker - based on what information)