We still have the Thetford toilet and the only time we have an odor is if the fan is on.
On a 2 year old TT we bought used, I encountered another problem best described as a poop pyramid though in that case, it was a poop mountain range. I was, after many many gallons of reverse flushing, a tank wand along with several hours unable to get rid of the odor though the poop was gone. That poop pile had actually backed or sloshed up into the underside of the toilet, evidently when I towed it home. The smell was actually in the plastic of the (Thetford)toilet and no amount of scrubbing, bleach or soap would eradicate. Only a new toilet cured that problem. Yes, I know the seal should have prevented the problem - but didn't.
Traveling with my DW Susan, a couple poodlepups and our 2014 Montana High Country 343RL, being towed by a 6.7 2011 F250 CCLB using a B&W hitch and OEM puck system