Setting spawn with /spawnpoint in Nether or End does not work.

I was unable to find a recent bug report for this issue, so I hope I'm not creating clutter.

I am creating a map in the Nether to test out and build with all of the new features. Before 20w17a, I was able to set my spawn in the Nether using /spawnpoint command (with nothing dictating the Nether, to be clear) but now when I die I get taken back to the world spawn. I have also tried to use /spawnpoint in the End, and that too did not work. I figure it may have something to do with a fix to an exploit with the bed in the Nether allowing infinite respawns, though I am not too sure.

Thank you for your time, hopefully this gets fixed soon!