Been around in various guises for many players, particularly those on older generation iPads.

Most likely a similar issue and is memory related.

Turning off the sound and weather effects (if the game has them) helps, as does closing out programs not being used.

As for the latest annoyance of having to open games twice as on the first open you can't get rid of the scratcher splash screen still haven't worked a solution other than restarting the game.