I don't know if I can repro the problem but I had a bit of a flaky wifi connection and the device hung at some point. I unplugged it and plugged it back in and then the device said it wanted to activate again using the same activation code. I tried to do that on the website but it said that code was already used. So I deleted the device, rebooted, and got a new activation code.
On a second occasion I wasn't getting updates on the website from the BrewBit. I tried a few things and then resorted to deleting and reactivating to resolve the problem. Again, I didn't take detailed notes to provide a repro.