Trying to set a special guest for an activity, but scope:special_option crashes the game

[WeeLittleSpoon]

I've stumbled into a bug that I think, unusually, isn't actually my own fault.

I'm trying to create a special_guests role for hunts. When you have a variable that is equal to a character, the game should automatically select the appropriate character from that variable, and then make them a special guest for your hunt.

The problem that I'm running into is with the scope:special_option.

This works:

    special_guests = {
        hunt_victim = {
            is_shown = {
                has_variable = plotting_to_kill
                scope:special_option ?= flag:hunt_type_standard
            }

            is_required = no

            select_character = {
                var:plotting_to_kill = {
                    save_scope_as = character
                }
            }
        }
    }

This crashes the game:

    special_guests = {
        hunt_victim = {
            is_shown = {
                has_variable = plotting_to_kill
                scope:special_option ?= flag:hunt_type_falconry
            }

            is_required = no

            select_character = {
                var:plotting_to_kill = {
                    save_scope_as = character
                }
            }
        }
    }

It seems every time I try to use the scope:special_option ?= flag:hunt_type_falconry inside of the is_shown block in hunts, it crashes the game. If you make the change when the game is running, switching the hunt type, it works as you'd expect, but once you restart the game, the game crashes the second you choose the location for the hunt.

I've tried a bunch of different things before finally whittling down the problem to this little thing. The .info file tells me that scope:special_option is a hard coded scope for the special_guests block in an activity, and I've found a reference of it being used in a couple other events this way, but for some reason the game doesn't like the falconry special option.

Just thought I'd take a shot in the dark and ask if anyone has come across this before, and if there isn't maybe something really obvious that I'm missing?