This is definitely happening. On Bedrock for Windows 10, Realms Plus, my Nametag wouldn't rename. I found a little way around it for the time being. When I put a water bottle that i had in my inventory into the second slot, after the name was in the Rename Box, then removed it, and it said nametag, but when I clicked the new nametag, it was gone, but a few seconds later it reappeared in my inventory, renamed!
Hmm, that is probably an optifine issue as the Optifines are not finished for 1.17. When I had a problem with the animations it was because of a performance toggle. Try playing with those to see if it helps, hopefully, they will fix it in the next optifine version.
The Bedrock Floor will be extended to -y 64 in the Caves and Cliffs: Part 2 Update 1.18, that will be at the end of the year.
Yea I see this too