I discovered I could just push the bearing back up into its plastic fitting. It’s pretty snug, but it might work its way out again. If it does, we can try an adhesive or re-engineering the fitting.

Tests with the standard half-inch squares show that this does fix the problem. No more wiggles!

I recommend checking the bearings before doing any critical laser jobs. Just lower the table a few inches to reveal the tops of the threaded rods. If all four bearings are fully enclosed in their plastic fittings, that’s good. If not, you can push the bearings up into the fittings. If that’s needed, please let me know so I can consider a more permanent solution.