Bug recreated on 1.20.62 singleplayer/realms and vanilla/1.21 experimental.

A map created in the end and then locked will update if the map is renamed.

Steps to recreate:

1. Go to the end dimension. In my testing, maps in the overworld act as intended
2. Create a map
3. lock the map in a cartography table with a glass pane. This map is locked as intended
4. rename the locked map in the cartography table or an anvil OR place the locked map in the cartography table and take it out of the right side without renaming it. These both trigger the bug
5. Observe your new bugged map. The sprite is still of a locked map and is still labeled as locked. The map is now updating and functioning like a normal map without a lock. This is irreversible.

Of course, the expected outcome is that a renamed and locked map will still function as a locked map and will never update