Need help with RNS-E

[Gytis]

Hellow all, my first post hear
I'am driving audi a4 b6 cab 2.5 tdi , and having some problems with rns-e unit, sorry for mistakes , my english is not very well
so the problem is when i put sound to the max , unit automaticly deacresa the volume down and when slowly comeing back to the max and when reach max again it deacresa the volume down and so on and on , until i turn down volume to 70% and when it's working fine ... i'am having not bose audio thanks for help

 

[NHN]

Sounds like the volume dial is faulty, if this happens when the car isn't moving, the circuit board ideally needs changing, I can do this if needed, pm me for more information.