It does it hot or cold.  I am letting it idle down prior to shifting or attempting to shift.  It's not all the time, but it's 90% of the time, it's only when trying to shift out of reverse.  Turning it off doesn't help at all, rocking the machine seems to help slightly.  I'll try the idler bearing and see if that helps.

I just picked up 2021 800 XC with 77-Miles on it the other day and noticed that from time to time I'm unable to shift it.  It seems to happen more often when I'm in reverse and trying to shift after backing up.  I am stepping on the foot brake that doesn't change anything.