OMD EM5 + Leica 25mm 1.4 Noise during focusing?

Hi all, just got my em5 today, amazing camera!!

One quick question, after i put on my 25mm f1.4 I can hear a strange rattling noise coming out from the lens during the auto focusing, is it normal?

I just sold my G3, so i dont have other m43 body to test it.

thanks in advance!