I have already tried a variety of ways to fix this, even up to reinstalling premiere.
I use ALs a lot, and haven't yet seen this behavior.
Have you added any effects to the AL? Does scrubbing work OK without the AL?
Scrubbing works fine without the AL.
As for effects, I added an RGB curves and an Unsharp mask to the AL. That's it.
Try with one effect at a time. See which one is causing your troubles.