Hide transitions from status "Status A" to "Status B" if the previous status of the issue was "Status B". If the user needs to return to "Status B" that should be only possible from another status, let's say: "Status C"
Add the following expression to enable the transition only if the previous status of the issue was not Status B.
If you need to prevent an issue from ever returning to the same status again, you should use the following expression instead.
Alternatively, you could also use the following expression.