Cannot invoke because "user" is null

[Brottweiler]

Type of bug

Error in console

/ess dump all output

https://essentialsx.net/dump.html?id=0efc594312ea4b9c9b1f8259ecbcdfec

Error log (if applicable)

https://bpa.st/NJ5LG

Bug description

After a server start, every unique player will throw these errors once or so. Relogging won't trigger the error again, only the first time the player joins. In the error, it references isAfk, but I have also seen isJailed and isMuted.

Steps to reproduce

1. Start server.
2. Let player join.
3. Read console.

Expected behaviour

No errors should show up.

Actual behaviour

The errors in the paste shows up. It does not seem to affect any functionality. AFK and Jail still works.