Get the following error when a player joins. using 1.13.2 Spigot. Vault was updated but not fixing the issue.

[WARNING] Error occurred while fetching a player's groups from Vault.
[ERROR] Exception Caught:
java.lang.NullPointerException: null

I would need more of the error log to tell if this is an actual issue in Vault, or if another plugin is doing things incorrectly. This seems like a plugin error though, not an issue in Vault.