After I updated to 1.19.30, I joined my realm after it updated, and I spawned in my house like always, except my map wall had a big black circle across a bunch of my maps, and it also happened to the other map walls across the realm. I tried fixing it by re-exploring those maps, but when I moved around, it would create more black circles. I did eventually fix my map wall, then to discover that it just puts the circle back on the maps when I exit and join again. I tried locked maps, but it even puts black circles on those too, even after I locked them. The way that triggered this bug was I had my realm from before 1.19.30, updated it to that version, then I had my previous map wall, and it should just display black circles across maps. I hope this gets solved, and thanks for taking the time to fix these issues.