OK, I’m happy but a little embarrassed for not figuring it out sooner.
Turns out the front facing edge had rolled up slanted and bunched, thereby making it a foot shorter than the back end. The front was taught, but the back had an extra 8-10” and sagged and flopped. No idea why it rolled this way (maybe rolled up in heavy wind?) but once messed up it continued to roll and unroll like that.
All it needed was to fully unroll the topper manually and then reroll while retraining the leading edge. Now all is good :). And I didn’t have to wait 4wks for parts from Carefree (everyone is out).