Submitted by volodya, also found by m9800, Emmanuel, IgorZuk, dec3ntraliz3d, igingu, adriro, Rappie, and descharre
Users will be able to purchase fewer NFTs than the project had anticipated. The project had expected that users would be able to purchase a range of variations using both text and emoji characters. However, in reality, users will only be able to purchase a range of variations using emoji characters.
For example, the list of characters available for users to choose from is as follows

For instance, if a user chooses to mint an NFT namespace using font class 2 and the single letter , then theoretically all other users should be able to mint font class 0 using the first emoji in the list, font class 1 using the single letter a, font class 3 using the single letter , and so on, the first letter on every class will be. However, in reality, they will not be able to do so.
I consider this to be a critical issue because the project may not be able to sell as many NFTs as expected, potentially resulting in a loss of funds.
Here is an how nft name and their svg will look like from what I described above. As you can see emoji replaced letters in the name.

This is a function that creates namespace out of tray.
canto-namespace-protocol/src/Namespace.sol#L110
There is a bug in this line of code where a character is retrieved from tile data. Instead of passing tileData.fontClass, we are passing 0.
Due to this bug, the names for all four different font classes will be the same. As a result, they will point to an existing namespace, and later, there will be a check for the existence of that name (token) using NameAlreadyRegistered.
Here is the test that you can run
Manual review, forge tests
Pass font class instead of 0
OpenCoreCH (Canto Identity) confirmed and commented:
