What behaviour is observed:

Force survival gamemode when player joins is not working, if a player leaves a server in spectator mode, when he logs in he's in spectator mode
This means that, if a admin/mod leaves the server in spectator mode and other player joins the server using the same name, he will be in spectator mode and he can teleport to other players and leak cords.

What behaviour is expected:

Players should always join in survival mode

Steps/models to reproduce:

Just install the plugin in any 1.17 paper server and try it.

Plugin list:

No plugins, only authme, tested it in a test server

AuthMe build number:

v5.6.0 snapshot build 2482

Configuration:

Force survival gamemode when player joins?

    ForceSurvivalMode: true