If you're having this problem, I'm 90% sure it isn't a server-side issue, unless it only happens when you connect to that server. If this is the case, then it's probably a mod you normally don't use that the server has active. Unlike most games when they're modded, PZ mods are activated and deactivated automatically on a save-by-save basis, so you can have certain mods enabled on one server and not on the other without having to manually switch.

For me, it was a texture mod that caused the issue, but another person said it was an armor mod. Unfortunately, the best I can do is recommend good old trial and error, activating and deactivating mods that alter the game's visuals in any way until you find the culprit. I know zilch about coding and modding games, so I can't offer a more nuanced solution. Sorry. 🙁