ER4PT microphonics: are the cables supposed to be this sensitive?

[Special K]

I exchanged my old, dying ER6i's for a new set of ER4PT's through ER's official exchange program.  I read about microphonics in the reviews before doing the exchange, but I didn't realize it would be this noticeable.  If I barely bump the braided cables or the plastic junction piece that connects the braided cables to the straight cable, I get that microphonic burst of static.  Does this sound like a defect, or are the cables really that sensitive?  Do all IEM's have this effect, and/or to this extent?  If not, what advantage do the ER4PT's have over IEM's with lesser microphonics?  The ER6i's and ER4PT's are the only IEM's I've tried.