Hi - I have a Jura Z5 that is making a groaning noise during the processing that got a lot louder recently. The sound can be heard around 0:06 and 0:30 in this video:
The Z5 was having some issues when the groaning occurred, where it seemed to be getting "stuck" in the cycle and would retry a few times before succeeding or just quitting (no error codes when it quit, though).
I just did a Brew Group refurb this weekend, and the system is running quieter - but the loud groaning is still occurring. It may be related to the Geared Motor assembly, since the noise didn't happen when I removed it ... but that could just be because the Brew Group wasn't being moved through its regular cycling when the motor was removed.