Pending Barrier box on black gate does not disappear

[EbiWan02]

Playing black gate the barrier box where mordor soldier spawn does not dissapear after the Black gate is opened, this traps mordor unless using /kill and spawns relocate.

 

[L_GS]

Spoiler: The temporary workaround when help is unavailable:

There's a 2 tall escape hole for normal sized players at the back left of the box (next to the wood pile), and wood from the nearby wood-pile can be used to build a set of stairs for trolls to climb over the barrier wall.

Spoiler: My best guess about what the problem is:

Based on what I've heard from Cotander, my understanding is that the barriers are meant to be removed as part of structure replacements used Black Gate animation.

So, my best guess would be that someone accidentally filled the frame that removes the barriers with structure voids where air blocks are necessary to delete the barriers.

Spoiler: How to solve this longer-term (if I didn't guess completely incorrectly)

Aside from the necessary immediate fix of removing these structure voids, it seems prudent to consider adding an invisible and passthrough block to prevent air from being accidentally replaced by structure voids. In this case, I would suggest using the minecraft:light block with level of 0 would work best, as aside from primary criteria of being completely invisible (unlike using string/tripwire), passthrough for players, and considered distinct for purposes of `//replace air structure_void`, it also doesn't stop manual block placement or become visible if given block update (unlike a wall with sides set to none & up set to false). (For anyone concerned about it setting the light level to 0, it won't do that, because light sources can't subtract from existing light level, only add to it -- mileage may vary for those using shaders made by someone too impressed with their own intelligence).