Some time ago we introduced a bug that would cause ChatLocalization objects to be created under the Chat service whenever someone joined a team create session. Some devs accumulated hundreds or thousands of these duplicate objects.
If you have any ChatLocalization objects under Chat that you did not create yourself you should delete all of them. They can have a small negative impact on join times and they serve no purpose.
Don’t worry: The root cause of this issue has been fixed. You should no longer accumulate any new ChatLocalization duplicates. ChatLocalization is the LocalizationTable used by the default in-game chat. It should now only be created by the server when the game starts, and only if it does not already exist.
We intend to make Studio automatically remove these duplicate tables when you open a place. This will take a few weeks to release though.
Thanks and sorry for the trouble!