If you are having texture troubles/issues in the general with Panthalassa try the following instructions when reinstalling the map.

Unsubscribe from Panthalassa on steam.

Navigate to your steam folders – you are looking for the following-

\SteamLibrary\steamapps\common\ARK\ShooterGame\Content\Mods\1065443232
\SteamLibrary\steamapps\workshop\content\346110\1065443232

Make sure that these folders are completely gone – delete from your folders and then from the trash bin.

If you want to be really thorough – restart your computer now.

Subscribe to the map and let it download completely.

This will fix most issues with corrupt downloads or files that are not helped by verification of your game files.