Calendar won't remain open with VoiceOver active on my iPhone 4

Hey all, I'm running iOS5.0.1 on an iPhone 4 32GB, with an untethered jailbrake applied through RedSn0w. Figured the jailbreak was worth mentioning because it might give me a few more options to troubleshoot, but I haven't posted this in the JB specific forum because the issue didn't start happening as a result of installing a tweak so far as I can tell timing-wise. With VoiceOver running, the calendar will open, hang for several seconds and then close. I've tried multiple soft resets, removing and readding each of my calendars, and double-tapping with my luckiest finger whilst standing on one leg, all to no avail. Earlier, I got somebody to open the calendar without VoiceOver running, and they were able to browse, add and remove events as per usual. Anyone know where to start with troubleshooting this? I'm pretty reliant on a couple of jailbreak tweaks and apps right now, so even though updating to a clean restore of iOS5.1 would probably fix it, I'd like to avoid doing so if at all possible. Cheers in advance Scott