Uh, oh! The FL2 started throwing a scan error this morning:
Restarting the app and rebooting the phone did not fix it, and both the NFC (scans) and Bluetooth (alerts) interfaces were offline. It recovered after an hour or so, and immediately sent an alert that my glucose was high.
From a web search of a few UK diabetic forums, it appears that the FL and FL2 have a built-in error prevention routine. If it detects an implausible reading such as a rapid rise or fall, it shuts down the interfaces for a while until the measurements stabilize. Better to report nothing than report flawed/dangerous information.
Long story short, it went offline in the 170's and climbing, and came back online in the high 200's and falling. It must have been a huge spike right after breakfast that triggered the error. There was a gap in the graph from the times that the sensor was offline.
I never saw this happen with the original 10-day or 14-day FL sensors, and will be keeping a closer eye on the FL2 to see if it goes offline again when I'm not looking.....