Reluctant to post this, but to add some advice that should help. When going finer, just go finer. When going coarser, go further than you want, say 6 or 8 marks and then go back finer to the point you want. I would say this is good advice for any Niche user, not just the few with a sticking burr assembly.
The only way the top adjustment ring can move round is if there is no real spring pressure on it, the burr itself obviously can't rotate.. The springs are more than strong enough, if they were not, every grinder would have this problem, including every one I tested. This can only happen if the burr assembly catches in the slide (tolerances are quite close) due to a technical issue affecting a very small number of grinders where an easy fix will be available soon....I'm not going to go into details, because it's not my place.
If you think about using the method above, by going past the point you want, it's far more likely all that pressure off the burr will allow it to pop up fine, then by screwing tighter to the grind you want guarantees a burr that is then being forced down onto the springs and experiencing the right pressure as designed. I used to work on precision lathes when I was younger, so the procedure is second nature to me (if you use a precision mechanical lathe, you will know what I mean).
Do not put pads or grips in the top ring or PTFE tape on the threads or anything like that. the grinder is designed carefully to centre the burr as the top ring is turned, it centres and bears down on it to do the adjustment. Pads in these areas (the inner ring press down point), will definitely misalign the top burr. The other bit of advice is to ensure the top black bit on the burr is clean of any silicone lubrication....however a small amount on the slide and the channel for the of the arms of the burr assembly can only help. To lube the slide, use a silicone spray (or a grease quite sparingly) or dry lube, spray on a cotton bud and wipe the bud around the slide and the channel for the arms...don't spray in there directly and don't use too much silicone. Also don't go too far down the slide, you don't want to get it near the grinding zone.