Possible bug number one:
I found a way to return a captive specialist with an attack going to the same base, you have to send the attack first and it has to be going to the nearest outpost that the player of the captive specialist owns, and after you schedule that you click to release the captive.
A lot of work for what seems like a detrimental thing, but I also stumbled upon a way to use it to my advantage which brings me to possible bug number two:
If you send above setup into a sub holding the same amount of drills, causing mutual annihilation, the game seems to resolve the battle with the captive being recaptured and this sends it off to your closest outpost rather than continuing with its release.
Again this may seem like a lot of work for nothing, but I found a situation where this seems to take advantage of what I see as bugs.
Edit: I was originally just attempting be a jerk and add another 11 hours to the time before he could receive his pirate rather than have him reclaim it with the attack he had just behind mine. That's how I stumbled upon this.