let me guess: you use reiserfs, right? if yes, it's known that wtmp gets corrupted their.
Only half true :) On the first one (7.3) I use ext2, and the problem is VERY much similar... It's apparently not a filesystem problem, and, as the kernels are also different, not a bug of a specific kernel version... BTW, both machines have an average uptime of 1-2 months, so it's not likely that wtmp get's corrupted due to system hangs or crashes (corrupted entries appear far more often then reboots, I mean)...
May someone from SuSE join this discussion?
Thanks Eduard
I had the same problem one year ago with Suse 7.1. After some investigation I found out the Loki rootkit installed on my system. Maybe this is not related, but you might want to check. Praise