The game restores blocks from the lower world to the upper after death in the lower.

Playback steps:
1. create two reborn anchors and charge them
2. on one of them you need to spend all the charges and then dying again you will find yourself in the upper world
3. left-click on a block and it is replaced by a block in hell
4. Right-click to return the block.
Note
1. When you restart, everything will return and it will be as it should.
2. The game is very slow with this bug.
3.He copies all the blocks from the coordinates in hell (I managed to copy the spawner) See photos
My opinion on how this happened
It seems to me that the game believes that you are in hell, because there is an anchor of rebirth, but you appear in the upper world and then the game goes crazy. Shows one and does the other.
(Sorry for broken English. I am from Russia and use a translator. Sorry)