I also ran into the ITI/hUR top quality syndrome. My odometer was dead on arrival! stuck on the same mileage for ever.
After getting the Speedo/Odo out of the bike, I opened it to check the root cause of the issue, and what could have caused it.
The worm screw that drives both the Speedo and the Odometer slowly ground itself until the thread was completely stripped.
My explanation, and you are welcome to challenge it, is that the cheap design and build made for no adjustment of the intersect angle between the worm screw and the driven axle as seen on the pictures. The assembly is held together by cold clamping the instrument chassis.
But thanks to LowRyter's tip, it appears I have a working repair solution now...
So for those of you who run into the ITI/hUR stripped worm screw, here's one option, the email below is dated stamped today, May 13th, 2021.