could it be that xe-0/1/1 by error is configured as a vc-port? That would explain why xe-0/1/1 is reported as non-existing.
Please check with 'show virtual-chassis vc-port' and if I'm correct, remove it from via 'request virtual-chassis vc-port delete fpc-slot 0 pic-slot 1 port 1' (please validate fpc/pic numbering before executing command!).