My 02 appears to be one of the good ones.. Right up there close to the 06, and better than a lot of legacy glass...
https://www.pentaxforums.com/forums/136-pentax-q/256849-comparing-adapted-len...ml#post2771342 UV Filter plus aftermarket rectangular hood...
Perhaps there is a lot of sample variability? Or possibly worse, durability issues that impact performance with increasing use?
Another possibility is 02 lenses manufactured during the Hoya-Ricoh transition. Hoya could easily have cut down on QC while this was happening. My 02 shown above is on an original Q - with its box and paperwork marked HOYA, so hopefully a falloff on QC did not happen...