Thank you lionz for replying, I might not have explained myself too clearly.
The following screenshot shows all the references to costume_unlocked_sunshine in the entire series of event sheets
So, as you can see there is no switching of the boolean at all (we just check it in a different area)
We have made the adjustments to the function, so now the triggering of it looks like this
Which runs the following function
We interact with the Fire Costume trigger, (as you can see in the first screenshot) and it all runs but still the Costume_Unlocked_Sunshine boolean is switched and not the Costume_Unlocked_Fire one.
So very strange!