On my '18 42DEQ (no rear bathroom), the two sliding doors on the closet use the same retaining latch on the roller mechanism. I've had one of the retaining latches open twice resulting in the door coming off the track similar to the OP's door.
Fortunately, I'm able to reach it, without much difficulty (and no trim removal) from inside the closet. Following the most recent retaining latch disengagement, I've tried a new tactic to prevent it from disengaging. It hasn't been in place long enough for me to be sure that it will solve the problem. Still, I'm happy to share what I'm "road testing":
I applied a strip of Gorilla Tape around the retaining latch in an attempt to hold it in place so that it won't become unlatched.
It's only been in place for about 1,200 miles. Not long enough to be sure that it'll work.
For those of you who need to remove trim to access that mechanism, it may be worth a try.
Take care,
Stu