The latter one is just Unity output for log messages, just ignore them (that's why I filter them for the log, they just clutter it).
The first one is a bit weird as that shouldn't be possible but on the other hand the worst that can happen is that the player will still be shown as online in the map atm.
Do you know on what occasion that happened? I.e. was it a normal client side disconnect, a kick by EAC, a kick by console, ban ...?