I inserted a new sensor yesterday and entered the code, no problem. The warm-up proceeded normally but the app opened up in calibration mode as if I had not entered a code. Weird! Then a message popped up that the app clock was making an adjustment (and I wish I’d taken a screen shot of that). Then the display reappeared as usual and the sensor appears to be tracking well.
FYI The calibration alerts are persistent with an alert sound that cannot be turned off. I learned this last night when I did not do the required calibration at 1 a.m.!
I had this happen as well last Sunday.
I ended up pulling the stopping the sensor, transmitter out, waiting a while, reinsert the transmitter and start the sensor again. Worked fine.
I refuse to calibrate and fingerstick on the G6 when I know it works just fine on it’s own.
Like @Hammer I will not calibrate (it doesn’t work; i.e. it didn’t work on the G4 and never again). I think you have every reason to pull the sensor, put a new one in and telephone Dexcom for a replacement. It would be very interesting to here the response.
I considered both options but since this sensor was tracking well (compared to the last 4 days of the previous one), I just decided to deal with calibrations. I think I am experiencing some post-vaccine fatigue.
Good luck! My experience was weird: the app asked for calibrations inconsistently and then had sensor errors on days 6 and 7. I pulled it and requested a replacement (using the online form)—no problem there. The replacement had the same sensor code as the one I replaced.