rear derailleur mounting bolt slack

[mickale]

Hi all...
I recently purchased an Orbea Mitis Chorus mix bike. After a month of riding, I've noticed that the rear derailleur has developed some sideways play in the mounting bolt housing...about a millimeter or so. I asked my guy at the LBS about this and he said there should be no play at all. But when I took it in and showed it to him he said it was not enough to worry about. So now I'm confused. He adjusted the shifting and for the most part it works fine. But I still seem to have some sporadic rear shifting hesitation and over-shifting whether going high or low. I think it might have something to do with the mounting bolt slack. I might be wrong, but just need to get a second opinion. Anybody else have a similar problem or am I just just being overly picky? Any response will be appreciated...
Thanks

 

[shannons dad]

Even brand new derailleurs have a limited amount of play in them. Don't worry about it.

 

[gclark8]

Simple:

If the bike is new and that LBS is the warranty service agent the the part is OK, its within tollerances.

If the bike is used or a brand he does not service then the part is stuffed and YOU have to buy a new one.