Mark Rein, Vice President of Epic, has posted on the company forums that the issue appears to be effecting users who are running devices with lots of apps causing memory to run out:
“For example if you have a large number of apps installed iOS must cache all those icons to give you smooth performance when you hit the home button.”
“Unfortunately the machines we tested on didn’t have massive numbers of apps installed on them so we think this how we think we missed this particular condition.”
“We’re working on a quick fix and will submit an update to the store as soon as possible. In the meantime we’re going to update the description in the iTunes App Store to mention that we’re aware of this issue.”
“One more thing. When apps run of memory at loading time that is something that is often fixed by restarting your device. So I recommend that people try restarting their device to see if that solves it for them. I say this because the game runs fine on my iPad1 which I restarted before playing the game.”
“For those experiencing the issue we thank you for your patience!”
EGM’s TAKE: It seems like Epic is aware of what is causing the issue so a fix shouldn’t take too long to release.
Source: Epic Forum