When trying to rename a previously named map within the Cartography table, the new name will not update and reverts back to the original name (ie. Map named "North" changed to "West" in Cartography table will maintain the name "North")

Steps to recreate this issue:
1) Name a map with the Cartography table
2) Try to just change the name (ie. not adding to its level)
3) Add map back to inventory to see name has not changed

Note: Maps previously named can have their names changed with the anvil in exchange for experience