With VanishNoPacket installed, some players do not show in the tab player list even if all vanish permissions are removed. I do not see any pattern to who is missing.

When you vanish, players who cannot see you also cannot see your entry on the tab list

I know that. No one is vanished. That is why I said all permissions are removed. Players are missing from the tab player list just having the plugin installed.

That's not possible. ._.