I see it says the plugin works with Grteleport, but I had a player tell me one used it to teleport away from a raid.
Is there a permission I'm missing for that plugin?
Or is it just suppose to work with the NTeleportation permission?

No, this plugin calls out to other plugins using the CanTeleport hook. If the other plugin isn't using that hook properly else doesn't have it at all anymore, then it won't work. Not really an issue with this plugin, but more so with the other plugin.

Wulf is correct.  The permission to block NTeleportation and GRTeleport are the same in NoEscape.  If one works, both should work.