Problem with drum tracks lining up in Flex Time

[rarkep]

I'm doing some light time adjusting of a multitrack drum take in Flex Time and I'm having an issue with the timing on just one of the tracks -- one of the overhead tracks wanderers seemingly randomly about 2/3 of the way into a 5 min song.

 

What I've done:

Created a group for just the 11 drum tracks and engaged Editing and Quantize lock.

Chose kick, snare and three toms as the Q-reference tracks (the toms are part of the rhythm of the song)

Unchecked the Group and then Detected Transients on the kick track in editor window.

Went through and removed any errant Transient markers and set all remaining markers to Zero Crossing (what a mind numbing task!)

Re-engaged the group and engaged Flex time with Slicing as setting.

Then quantized the group to 1/16th notes with Flex & Follow with Align Bars + Beats.

 

From beginning of the song everything sounds great but about 2/3 way through one of the overheads drifts significantly ahead of the rest of the drums. It doesn't stay stable, either. Sometimes it realigns but then drifts again. Before doing the flex time the drums were fine. No issues with the tracks lining up.

 

Any ideas?

[logicben]

Unchecked the Group and then Detected Transients on the kick track in editor window.

I can't remember disabling groups on multi-tracks when using flextime.