I seem to be encountering the same issue in 1.17.1, though I am using a few vanilla tweaks, and it's possible that the creepers simply aren't registering trapdoors as walkable blocks, which is a separate issue.
[media]Fairly confident that is intentional in that the X/your player marker are too large to mark precisely where the treasure and your player is. I've found that approaching the X from different directions helps me find the treasure, and you'll notice that the perceived location of the X changes depending on which direction you approach it from. I'd recommend walking towards the X from each of the cardinal directions until you find it.
Yes, we started it in 1.15.2 and updated it to 1.16.1 and then recently to 1.16.2.
Killed the ender dragon and brute and both registered- all good! Sorry again that we updated before testing, but hopefully 1.16.2 was in fact the solution.
Just killed a vex in both the original Realm before it closed and new Realm and both registered towards the advancement, so something happened between now and the last time I killed a vex. Wish we hadn't updated before testing this, because we don't know with certainty that updating was what fixed the issue. I will comment again once I kill the brute and ender dragon.
Yep, haven't gotten to a brute yet. Will try that and the other two again. We've just switched the Realm ownership today, fyi, in case that will matter.
I've just attached the stats and advancements jsons. As you predicted, updating to 1.16.2 didn't do anything. It seems the two mobs that aren't registering in advancements are the ender dragon and vex (great, have to kill those again).
Edit: I should mention that I did receive the Free the End achievement and that the ender dragon I killed was the first respawned dragon.
It's a Realm- I'll contact the admin about getting my files (unless there's a way for me to access them?). Once we update to 1.16.2 I'll let you know if previously killed mobs register correctly.
I experienced this issue in the 1.16.1 Nether- in one instance, only my pickaxe remained in my original death location, and about 20 blocks away were some other miscellaneous blocks from my inventory. Died from fall damage due to a hoglin throw, so there was nothing that would have propelled those items that far away. In the other instances, other players could not find any of their things.
Sorry, I didn't come across the duplicate- thanks for the link!
Are they sitting? Will they teleport to you if you get far enough away?
Make sure you are not using a reduced debug screen- this toggle can be found in the options menu.
Having this issue trying to upgrade a 1.19.4 realm to 1.20- Initially thought it was due to vanilla tweaks but even trying to upload a totally vanilla file I get the same error message.