Random reboots after 6.1.3

After updating to iOS 6.1.3 my iPad 2 and my iPhone 5 are randomly rebooting. It happened only once on the iPhone but it has happened 3 times on the iPad so far. At first I thought it had to do with Skype because the iPad rebooted (the two of three times) when I was on a Skype call. That doesn't explain the reboot on my iPhone because there is no Skype on the iPhone.

Does anybody else have the same problem? Is there a solution for this?