I've noticed this occasionally over the past few months:
 
If I'm playing back a project, then skip to another section in the song using the marker drop-down in the control bar while continuing plackback, sometimes a few tracks/busses/auxes will continue playing from that point instead of moving to the designated marker. 
 
For example, let's say I have a Verse/Bridge/Chorus. In the Chorus I have a bunch of gang vocals come in. I'm playing back the project, nearing the end of the bridge (just before the gang vocals jump in), and I select "Bridge" in the marker drop-down to go back to the start of the bridge. The playhead jumps back to the start of the bridge, most tracks follow suit, but then the gang vocals start playing, as if they didn't know I was jumping back to the start of the bridge, not moving along to the Chorus.
 
When this happens, if I stop playback then start it back up again, everything gets back in sync. As far as I can tell, this only seems to happen when skipping through the timeline during playback and using the marker module in the control bar. If playback is stopped and I use the marker module, everything seems to be fine. 
 
In regards to what's affected, I've noticed it on tracks that are routed to an aux/patch point, and also an instance of AD2 (simple instrument track).
 
Has anyone else noticed this type of behavior?

Can anyone give this a try to see if they can replicate?

This can happen with MIDI when jumping back at the end of a loop due to a bug with MIDI FX that interferes with buffering, but I've never seen it happen with recorded/rendered audio or without MIDI FX in the project. I'm assuming that jumping back to a marker would be subject to the same MIDI buffering issue as looping, so that might explain your AD2 issue. Are there an MIDI FX anywhere in the project?
 
As for the audio issue, there could be something going on with Aux tracks, specifically. I'll see if I can repro.

I typically freeze MIDI/synth tracks before I start the mixing phase, although I'll have to double-check because maybe I missed it this time. But because I've seen that sort of behavior before with MIDI I didn't think much of it until I started seeing it with audio sources.
 
I'd never seen this before until recently, but once patch points/aux tracks were introduced I've been using them like gangbusters, so that does seem like the most likely culprit. IF anyone can replicate this, of course. If not, it's probably Gremlins.

I just remembered (and confirmed by retesting) that the MIDI FX issue got fixed a while back.