class Choice {
	String tag
	String branch
	@Override
	String toString() {
		return tag  + ' / ' + branch
	}
}
def obj1 = new Choice(branch: '1', tag:"3")
def obj2 = new Choice(branch: '2', tag:"4")
return [obj1, obj2] 

The following groovy script works fine for Active Choice parameter, but broken for Reactive one.

For some reason, Reactive version ignores toString (yet it shows correct string for a second), showing "Object" string instead:

First paramater is reactive, the second is non-reactive