I've got my JM20, and... there are clicks when launching a track. But! they are not universal!
Android phone
Mi Music (Xiaomi) - no clicks, nothing's cut!
YouTube Music - no clicks, I don't think anything's cut but didn't test too much
HiBy Music - clicks!
HiBy Music in USB exclusive mode - clicks!
Windows 11 23H2
WinAmp 2.92 (shhh) - clicks, but not 100% of the time, seems to be a bit track dependent, but even the most clicky ones can start without a click, the beginning I think is slightly truncated though
Similar behavior seems to be with CS-Pro CS43131 (possibly SA9312L) dongle as well (note CS-Pro designation was also used for an earlier CS-Pro CS46L41, and is mistakenly used on renders for CX-DAC CX31993 + Max97220 dongle).
Creative SoundBlasterX G6 is fine/free of clicks though (CS43131 + actual discreet amp).
Doesn't seem to be affected by impedance - tried with 32Ohm Yincrow X6 earphone, 64Ohm Faaeal Snow-Lotus 1.0 earphone, and 300Ohm Sennheiser HD600. Also tried defeating the impedance sensing (build into the chip) by launching it open with 3.5mm to 3.5mm 90 degree adapter, but the clicks were still there. I made Windows stop playing sound out of both dongles though, and I have no idea why, reconnecting them didn't help, neither did different USB C to A, OS still saw them, power was on (CS-Pro has LED), got an OS popup about device not working correctly once.
Honestly I won't be mentioning to people any CS43131 dongles which aren't confirmed to be click free, no matter how good their measurements are. I feel like there should be a big WARNING on the review/measurements pages, about the issue. Although to be fair, I only noticed the clicks because I read about them, I've ran CS-Pro CS43131 previously and just didn't paid any attention to them. Too bad, because I actually like the sound out of JM20, at least with earphones, cause imo it is not enough for HD600 (I knew that though - I bought the dongle to be used as DAC for an amp).