Logic Pro Session Player tracks have extreme latency if you customize your projects in any way.

Session player tracks lag by 1/4 measure. I spoke with a tech about 6 months ago, and we came to the conclusion that this in fact was an issue. I fixed it by deleting my Plist. After removing all my preferences I use for my projects in Logic, the Session players worked again and were in sync. As I started re-adding my project settings, Session player tracks lost sync. I just checked in 11.1 hoping it would be fixed. It is not.

It's a pretty egregious bug that needs addressing. They are basically unusable otherwise.