I experienced some funny business (technical jargon) when I hired Assassins, immediately launched one of each on two subs, both with drillers and one other specialist (a Smuggler and a Thief, respectively) toward two different outposts.
I was experimenting with arrival timing and driller count, and, multiple times, the game wouldn't allow me to cancel a sub launch, or--if I emptied the sub and tried to launch another with drillers and specialists--tapping on the second sub would show the first sub's 0 count, even though it would appear to launch properly with personnel when I scrubbed forward in the time machine.
I closed the app and switched back and forth between my iPhone and iPad several times, but I experienced the same uncancelable (is that a word?) subs or erroneously displayed 0 count on both devices.
I was trying to set up a complex maneuver at the last minute that needed to be precise within two or three ticks of the game clock, so it nearly gave me a heart attack when everything went all wonky. Haven't experienced the same problem again in the last several hours, though.