I know, this is just the feedback tracker.
My workaround for this silly bug is to use another arsenal close to the command truck (with the help of the other asenal, supplies in vehicles around are recognized propperly by the deployed command truck ). for instance: If you first place an arsenal truck (or medical van), then an transpot truck and finaly[!] the command truck all supplies (in the command truck, in the transport truck and in the arsenal truck) are recognized and taken into account. However, the other trucks will despawn just like the supplies you drop from the command truck. To circumvent the other vehicles from despawning, i use an NPC / AI- guy, which i order to the passenger seat (you have to sit at the driver seat while ordering him to go in the vehicle). you even can open a new group for this npc passenger and when he is sitting in the vehicle just leave the group since his soley task is to prevent the vehicle from despawning)
In this combination(arsenal truck, medic van, supply truck), i build something like an full fledged FOB at strategical, important key positions, which is not shown in enemy maps.