SMC K 18/3.5 - loose filter switch

[Pawel Bartuzi]

May I have a question regarding SMC K 18/3.5? The question is: is it 
normal for this lens to have a slightly loose internal filter switch 
(together with external filter thread)? There is approx. 1 mm of "play" 
in my example - the front element however is stable and doesn't move.

If it is not normal does anybody know if there is an easy fix for the 
issue?

--
Pawel