Obsidian pillars not generating properly

I have this too, but I captured the whole thing on video

20w20b.jar - server with 1 other player online

Secondary effect: After beating the dragon, the one end gateway that I already had is either being overwritten, or no new end gateways are generating.

I've dumped the raw footage into some youtube videos

First fight - https://youtu.be/9zV2ATpNpyI

Second fight (had F3 shown whole time) - https://youtu.be/u-m5fOeaFoI

Please attach the backup copy of the world before updating