I have noticed two problems that have cropped up on IOS and Android.
The 1st is sometime when selecting a boost (i.e. additional gem boost) and you need to invest ISO to get the boost sometimes it becomes unselectable and you have to go back to the teamup/boost screen and then select the slot again to get the boost.
The 2nd problem is sometimes when notifications pop up (you have been attacked, recruit so-and-so 'cus they are so awesome etc.) when you dismiss the notification it says no events are available. I usually have to force close the game (Android and IOS) and restart and then all is well and nothing is lost but time.