Well, this has been a fun day. I called TT support. First person told me to remove the app and reinstall it. Did that, didn't help. Called back, and they suggested I roll back to an earlier version of the app. Tried that, didn't help. Called again, did a few more clear flashes, didn't help, he suggested I remove the map and re-install it -- didn't help either. I've also done a factory reset, with no luck. Any other suggestions?