What f/w are you on? What apps do you have installed?
I noticed that w/ Customize 1.18 on f/w 1.1.2, My Safari and some other 3rd party apps would randomly crash. I uninstalled Customize v 1.18 and it was resolved, instantly. The funny thing was that I had only used it to change one string of text, and that was to change the 'Enter Passcode' to 'What's 1 + 1?'.
The problem must lie between the 1.1.2 firmware and Customize 1.18 release. I also on first install of Customize 1.18 had some apps that started to function funny. So being that it was fine before I installed 1.18 I just removed it and reinstalled it. Afterwards, problem resolved!