Zyx R50 problem or not?

Hi all,

Need a help with my strange situation: I have Zyx Bloom R50H with Cinemag 1254, connected to EAR834P. The tonearm is TransFi Terminator. All was OK at the beginning, and suddenly the right channel become stronger then the left one. No distortion in the sound just the balance of the sound stage is more to the right. I have checked everything, cables, connectors,… all fine.

A friend of mine got me his Supex 900 cartridge, and all is fine. No problem with the channel imbalance. The same is with old Pickering  MM cartridge without the SUT, also no problem.

Then I gave the Zyx to my friend for the test, and, guess what, no channel imbalance in his system!?!?!?

HEEEEEEEEELP!!!