Ghosted entities plague the map - empty vehicle seats (

[Pantho]

So I've added a few passenger seats to vehicles and been using this method to do so:

[LUA]
local Seat = ents.Create("prop_vehicle_prisoner_pod")
Seat:SetModel("models/props_phx/carseat2.mdl")
Seat:SetKeyValue( "vehiclescript" , "scripts/vehicles/prisoner_pod.txt" )
Seat:SetPos( theCar:LocalToWorld(car.firstseat.Localpos))
Seat:SetNoDraw(true)
Seat:Spawn()
Seat:Activate()
Seat:SetParent(car)
Seat:DeleteOnRemove(car)
car.Passenger = Seat
[/LUA]
However I've been having an odd issue, I remember I used to also get this issue in GM12 when using sickness and vmod (Not using those 2 now obviously). The issues is what after prolongued play the map gets plagued by invisible entities that I cannot track by any means I can think of.

They cannot be found by GetEyeTrace() on server or client, FindInSphere() around the location doesn't show anything weird.
While stood on top of one of the invisible pods:

lua for k,v in pairs(ents.FindInSphere(pantho:GetPos(),200)) do print(v:GetClass()) end
Remote print: player
Remote print: predicted_viewmodel
Remote print: keys
Remote print: weapon_physcannon
Remote print: gmod_tool
Remote print: pocket
Remote print: weapon_physgun
Remote print: weapon_mad_fists
Remote print: physgun_beam
Remote print: predicted_viewmodel
Remote print: predicted_viewmodel

I really cannot think why this is happening, the invisible chairs remain even after removing all vehicles from the map. I'd assume it was a clientside only issue but the chairs cause damage to players when colliding.