Strange hardly noticeable but very important PDC issue. 2 different approaches I noticed it happening.
1st time
Insert an IZotope Neutron plugin on an FX buss before or after the FX.
The FX wasn’t set to 100% wet yet.
Noticeable phasing sound… what the! Spend some time thinking!!!
Deactivate Neutron via the bypass in the mixer
Reactivate Neutron via the bypass in the mixer
Sound is now correctly in time
2nd time
Using Shaper Box Volume Shaper on the master stereo bus, set to 1/4, simply to show the waveform relative to speaker movement (but static in how it displays) and how waveforms add together when soloing and muting tracks. When I solo’d my open hat, I noticed it was ahead of time. Thinking this might be related to the above issue, deactivating/reactivating various Neutrons in the project fixed the issue, once finding the right one.
No idea what’s causing this, seems to be random.