В сегодняшнем обновлении эту ошибку исправляют.
Из патчноута:
"Vehicle Deployment
This update includes some new additional logic to address the problem of spawning as a Tanker, Pilot, or Cavalry soldier
without your mount. We have also made some fixes that should prevent the player from getting the incorrect kit when
spawning into a vehicle, for example spawning as a Cavalry soldier when spawning into a Tank. In some extreme cases,
the player maybe blocked from spawning if a vehicle cannot be spawned. This can happen due to positioning of other
soldiers and vehicles in the world, and should be rare. Previously the player would be spawned without the vehicle; in
the new case, the spawn flow will be aborted and the player given a “spawn not available” message."