On Windows XP (Tablet PC Edition), Live 3.0.2 (I'll download 3.0.3 shortly)...
I can fairly successfully reproduce a bug that will change a loop from saying it is 4 (or 8...) bars to 3 (or 7...) bars.
To replicate this. While a loop is playing click on the warp button. It seems to always or almost always switch from seeing the loop as a 4 bar to a 3 bar. The loop still plays in time, so I think there is just some sort of off by one Counting bug. Once the count gets to this state I have been unable to find a way to 'fix' the count other than to remove the loop and then bring it back into the set.
Once I have downloaded 3.0.3 I'll post if the bug is reproducable there as well.
Greg