Noisy Sigma 30mm f2.8 EX
You don't have a problem. This is what they do.
I just received mine (for my OMD) and the rattle seems to be the same. But when mounted, there is no more vibration and the quality is very good. Paid just USD 199 for both the 19mm and 30mm in a promotion from B&H and do not regret it at all. See the sample file attached (no PP).