This is not a bug, it's correct behaviour, but it's very easy to overlook, especially noting that the special guard
[else] can be simply typed in and can't be selected as a LiteralBoolean! This means that if you are using [true] on one edge and [else], the 1st one [true] has to be selected via the specification dialog, and the 2nd one [else] can simply by typed in.
You'll know you've done it correctly for a true/false when the Guard field in the specification dialog shows a checkbox