It would have been better if you had reported this in the plugin GitHub/Discord server directly. This is a long standing bug with bStats not necessarily caused by Holograms directly, but I never understood it entirely (something with the order of loading plugins, which changes once mods are added/removed, I guess).
Two options to fix this:
- The most simple solution: Delete the
config/bstats/temp.txt, and reboot the server.
- Or: Download the newest version which uses the newer bstats implementation: https://ore.spongepowered.org/RandomByte/Holograms/versions/3.2.0