Issue I have encountered on a custom modpack me and some friends are playing. I had a client DC after using the Ore Vein Finder, and when I logged back in the old circles did not disappear. Can still use the Finder, and new circles disappear as they should. Turning off Ore overlays on the map does not fix the issue. I have also tried placing a new circle over the old one, and tried waiting them out after noticing they were not going away. Even delated my map to see if that would fix it. You can see the Lapis vein I found marked.

Using:
quilt-0.26.4-beta.6
create-fabric-0.5.1-f-build.1417+mc1.20.1
createoreexcavation-fabric-1.20-1.5.4
journeymap-1.20.1-5.10.3-fabric

Update: Now sure why, but after starting up the modpack today after the server's daily reset, it seems to have fixed the issue.