This came up in training today, on an Ion XE running the current software version:
Cuelist 2/: two cues set to loop (ie. cue 2 linked to cue 1, both cues have follow times). Running on a playback other than the master playback.
Double hit CUE to get to the cuelist view.
cue 2/ MOVE TO cue 3/ enter
Console locks up, clock stops running, only seemed to be recoverable by powering off/on.
It's a slightly quirky set of circumstances, but the end result is not ideal!
Have a showfile and logs if they're of any help.