My 35mm ‘lux also ‘developed’ a lose aperture ring. Initially when I bought the lens from the Popflash the ring was so lose that I returned it and exchanged it for a new one. The new one wasn’t exactly ‘tight as a drum’ but it didn’t rattle. However, over time I noticed that it started rattling and I observed the free-play along the optical axis of the lens. The ring still clicks nicely in its groves when turned. This time, however, I contacted Leica technical service department in Germany and they ‘assured’ me that some free-play is ‘normal’ and that it does develop over time on Summilux lenses and that there is nothing wrong with them. I am still not so sure about the whole thing especially after reading numerous reports of the same problem that sometimes resulted in ‘leans-separation’. Since the lens otherwise performs flawlessly, I’ll use it until the warranty period is about to expire and then send it for an adjustment to Popflash.
Honestly even if the lens is supposed to develop some rattle over time I think that it’s unacceptable by modern standards. Too bad, it’s otherwise super nice lens.