This bug is occurring in my 1.15 world
I just encountered this problem on my Xbox one realm. It has been quite a while (many updates) since I have explored a new woodland mansion in my world. After finding a new mansion I was surprised that all vindicators where not hostile until attacked. Vindicators that are part of pillager raids are not bugged and are hostile.
These achievements also will not work on my xbox one realm
This problem has cropped up on my xbox one realm while I am trying to contain all hostile mobs. Wither skeletons are the only mob I have found that I am unable to use a nametag on.
This has happened to me several times playing on my xbox one realm. The first couple times it happened I figured I was being careless and didn't realize I was low on health due to withering, but it just happened to me immediately after entering the nether with no doubt I had full health and having fully enchanted diamond armor. I did not even see the blaze it happened so quickly, only heard the fireball noise and was dead immediately. I was able to recover all but one piece of armor; but the piece will take a while to replace. This bug is absolutely killing the nether experience and needs a fix immediately!
I tested this after seeing a reddit post on this bug. I was able to reproduce it in 1.16.3 when falling from exactly 49 blocks, the player dies and the boat breaks into planks & sticks.