Yep, same issue I just had. Apparently I was using iCUE version 3.38.61, and all the sudden I had no lights indicating my temperatures, and no temperature sensor selection. Your explanation sounds reasonable as to what happened. Pretty scary if you are relying on this for anything other than "pretty colors".
Interestingly, when I click on "Check for Updates", I get "You are using the latest version of the application". So, I get that maybe this is the latest version of 3.x, but how about a little help, maybe saying that 3.x is unsupported, and recommending a link to 4.x?
I share the sentiment of the OP, c'mon Corsair, you are a $2 billion capitalization company, it's not like you are a mom & pop operation.
