Baseplayer / Network group issue?

Various issues
Affected players not able to see other players, animals, zombies, bases etc outside of a certain area causing them to be attacked and killed by things that they can not see.
Affected players also not able to wake up after teleporting.
Affected players can have weapon attachments visually disappear from their weapon when leaving a certain area.
Affected players riding vehicles will have the vehicle disappear from under them when leaving a certain area. Vehicle remains visible to other players.
Non affected players can not see affected players outside of a certain area.

Issue is sporadic and not able to be reproduced at will at this time.

Suspected players were being parented to an entity and the issue would occur when leaving the network range of that entity but found this is not the case when a player last had this issue on EU Scourge. (See below image for proof the player is not parented to an entity)
Currently as far as I can see it looks like the affected base player stops updating it's network group as the player moves around the map causing them to only load/render things in that same network group/area.

https://discord.com/channels/333343032328060939/370256314364067840/1305628516070723646

https://discord.com/channels/333343032328060939/370253862013239298/1309553913955090433

In the below image I was following the affected player while they were moving around the map, my entity ID is 1678675 and I can identify this based on the items parented to me from my inventory. Entity ID 433252 is the affected player. Notice how while following them around the map my group has changed between the 2nd and the 3rd set of results yet the affected players group has remained the same.