hey buddy,
I had the same/similiar issue.
It updated once to 3.08, then I noticed double types of some keys.
I tried to force firmeware update and ran into the samme issue as you.
After an hour or so of trying different versions of iCue (even old version of corsair link) I gave up.
I had success the next day, when I installed newest version of iCue on my laptop (never had it installed there) and forced firmeware flash to the old 2.05 firmware version
(get / see it here https://github.com/mattanger/ckb-next/blob/master/FIRMWARE )
For now my problems are gone, I currently stick with 2.05 firmeware, did not tried to update to 3.08 on my computer again.