Same issue
I got to 100% on achievements after the last ones were added and managed to get all the rewards according to the game, but I’ve checked today and I found about 6 new achievement based items in the lists of all items, yet don’t appear next to an achievement in the achievements list and the will not identify which achievements they are connected to. I was able to collect two of them, but cannot collect the others. One I could get was the blacksmith apron. On I couldn’t get was a piece of headwear that seemed to be an autocrafter on top of an autocrafter. It would seem that new rewards have been added since the achievements were added and since I have completed them already I cannot claim them.
Must be a spawn issue. The seed was first started in 1.19, but the chunk loaded after the 1.20 update. The exact same issue was reported on Reddit 2 years ago once. No other instances seem to be recorded. Here is the link to that person’s post. https://www.reddit.com/r/Minecraft/comments/up46xv/unknown_map_does_nothing_bedrock/
Seed: -1251937210
Village location: X: 1,224 Z: -1,400
Bedrock 1.19 offline single player peaceful mode. A named rabbit was tied to a single fence pole on an area of flat ground that included the spawn point. About an hour of mining happened below the area during one session. The following session less than an hour was taken to sail to another area and back. Upon returning the rabbit was missing.
I’ve used Minecraft on iOS to test the details given by KR. One attempt generated 3 separate pieces of paper, but two other attempts created the 3 unknown map 0 level 0 situation. They were blank to begin with, but quickly filled in with a map of the area.