Had some time today, so reverted to 4.33.138. And, of course, all is well, or at least as it should be...
A bit disappointing, but since this is my first disappointment with Corsair (contrary to e.g. competitor that starts its name with R and end with same 🙂 ) while using their stuff for a decade now, I'll let it pass and patiently wait for better solution (or iCue 4's EOL) 🙂