indestructible island ends completely

Bedrock End Island Glitch

So basically I recently cleared out the end island in creative using a variety of methods such as tnt, using my hand, command blocks and structure blocks. I was very pleased when it was done, but now whenever I leave the end, or the world, this stuff keeps appearing at the bottom of the end. I don't know why it's there or what to do about it, but if I can't can't do anything about it, it will ruin my build idea that I really want to do

Does anyone know what I should do?