Symptom:

1. create a Select List custom field with an option containing "&" in its value
2. add that Select List field onto transition screen
3. select that embedded "&" option before transitioning
4. transite that issue in Task Board, in transition screen, user finds that the first option instead of selected option is displayed for that Select List field
5. after transitioning, the value of Select List field is reset to the first option.

Workaround

So far, we can't find the effective workaround.