Attempting to remove several instanced static meshes on box trace, some remain on final hit trace.

I am attempting to make a mining mechanic in unreal engine 4, that is similar to minecraft. I am attempting to remove multiple instances from an instanced static mesh using a box trace to detect the blocks, and apply damage. The damage seems to be applied evenly, but when removing the instances when they run out of health, some instances seem to be left. I have attached a screenshot of my box trace. Why are some instances remaining when they should be evenly removed?

miningBug

I managed to solve this with help from another thread linked bellow

Yup you have to sort your instance first, then remove.

This applies to all Instancing.