Already posted this in questions section, but this might be a bug so I post it here again:

I played around a bit with the time machine to see the outcome of some strategies. I'm pretty sure I canceled all scheduled subs but now there is one left. The problem is that I can't cancel it. The x in the time machine menu does nothing and if I jump to the time when it starts I can tap cancel launch and it cancels, but a second later it is scheduled again. I still can modify the number of drillers and the specialists that are traveling with the sub and the changes are saved. This way I can minimize the casualties by sending just a single driller with no specialist, but I can't cancel it. Is this intended or a bug?

Some people have reported similar things and the dev's are aware of it and working on it.

For now, if you don't want the sub to go, just leave it at 0 and then it won't launch.

I can't set it to 0. 1 is the minimum unless you put a specialist on it.

Ah, well then as you said, setting it to 1 limits the loss and depending on where it is going you could just gift it to avoid any aggression.

Like I said, the dev's are aware of the issue and are working on it.

Just hope it doesn't happen if you're attacking a sub with a pirate. You cannot remove the pirate if it does.
I believe the dev's indicated they've already released a patch to solve this, and it's making its way through Apple's approval process.