I've encountered this issue both in the (now unsupported) 1.9 and the current Community build and it is driving me insane. I am currently playing on my own using the Community Build, with a quite of mods including RHS and ACE- however, this same issue doesn't seem to occur on an MP server I play on.

I capture a vehicle, and take it back to my HQ. However, upon attempting to garage it I get the error "Only rebels can add vehicles to the garage". Given that I am the commander, I am very confused as to why this is happening.

Is it a simple fix or setting that I haven't set, or is this a known issue?