Yes, I've seen this too, it seems to be related to iOS 7, it never happened on iOS 6 afaik, but it's not always reproducible, so it's kind of difficult to fix, though I have some ideas for workarounds.
Also, FWIW, I was running iOS 6 (NO jailbreak) on an iPad Mini when I saw the crashes. The only way to get around it was to kill editorial and restart it (it would still be in the multitasking list after the crash), but even that wasn't 100% reliable.
A prefix might be an option, I could imagine using something like var-xyz=foo to set the variable xyz... I probably won't change the URL scheme in the next update, but I'll keep this in mind.
