A while back, I found that one of my stones (a single 1000 grit plate) was out of whack. I identified that the plate was not positioned properly in the pocket. It was caught up on the end border of the plastic. I just cut the end of the plastic off and the plate laid itself flat into its proper position.
Here are some photos I took:
This shows how I could slip a scalpel under the end of the pate.
This shows the difference in height of the two plates:
This shows how I cut off the end of the plastic with a hacksaw blade:
This shows how the plate snapped into position:
If your problem is similar, I suspect that the the plates may not be the correct length and/or not installed properly. That said, the hacksaw is an easy fix.
By the way, I used that stone for two years before I noticed the problem. It showed up when I started using my VSTAs regularly.
I think I’ll go look at my new stones. Hmm….