This is a known issue that we're working on now, and we would appreciate detailed bug reports to help us to isolate and verify the problem.
Please, submit detailed bug reports here:
If you provide your contact information, we'll be reaching out to some of you.
The issue is that the information held by the render thread is getting out of synch with the information held by the UI thread. This kind of problem can be worked around by restarting the application, purging the caches, or closing and reopening the project---all of which force a re-synchronization of these sets of information.
Having the same problem. Has made using AE impossible.
If you'd like to help us to test the After Effects CC 2015 (13.6.1) update---which fixes this bug---you can request access to the prerelease testing program here:
Choose the "Private programs" tab and click Apply to apply for the "After Effects CC 2015 (13.6.1) patch update" program.
The After Effects CC 2015 (13.6.1) bug-fix update is available. It fixes several bugs, including the one being discussed on this thread.
Let us know how things work after you have installed the update.
Thanks for getting back to me Todd! Although it does seem better there are times when I have zoom in and out of the timeline in order to prompt a preview refresh on the current frame.
All the best