While I just assigned routes to some of my submarines, I locked my phone's screen accidentally and unlocked it right away. Then, out of nowhere, 3 more subs with no driller on them are ready to launch from one outpost to destinations I previously assigned to others, and one more sub in another outpost "volunteered" to launch 10 hours later to my ally's outpost. When I tried to cancel them, they just kept popping back up again, endlessly.
Eventually I managed to cancel the 3 in one outpost, but the one set in the future was not going to give up. No matter how many times I reopened the game or logged out and in, the sub just reappeared "launch in 10 hours" immediately after the cancellation.
It bothered me because it occupied my space to issue future order, which cost me a valuable opportunity to attack when I was sleeping. Besides, I do not know if it will do this weird stuff again.
This is my third day playing the game. Everything is going great and I admit it is indeed an outstanding strategetic game. However, stability of mobile app needs to be improve much more.