Yet another crashing issue
I awoke this morning to find that when I complete a mission and haven't got all the keys the game crashes when I press the arrow button to view the ad, it at least lets you go back after the crash to get at least some materials. Also after completing a node and being awarded coins and pigs and materials the game will crash when attempting to view an ad. I am not sure if all of them are awarded when game is reopened.
I have reported issue to Rovio.