This bug is still present in 10.6.1.
Been testing a setup for over the internet recording and have been attempting to figure out sync/clock issues. Initially thought it could be tied to the looping thing, but now believe it's literally a tempo issue in Logic.
That being typed... I did a looping exploration and found in 10.6.1 these are the tempos that Loop without issues:
224, 210, 200, 192, 180, 175, 168, 160, 150, 144, 135, 132, 128, 125, 120, 108, 100, 96, 90, 84, 80, 75, 72, 64, 60, 50, 48, 45, 40, 36, 32, 30, 25, 24, 20, 18, 16, 15, 12, 10, 9, 8, 6, 5
Any other tempo without a workaround as noted in an earlier post - will not loop perfectly. Can anyone see the math pattern? I can't.
This is specifically audio related. Sample rate does not matter. This only affects audio regions as MIDI regions now loop at perfect at any tempo.