I sometimes have issues with losing signal, which is frustrating. But overall it was a lot better than when I was using G6 (every sensor failed around day 6) and my blood sugars are a lot better when I am using the G7 and ControlIQ on the Tandem than any other sensor I've used.

I have had some issues also. One they don’t stay on and they are about 60 points off. I was in the ER and it was fine on my end but high when they manually tested me. So, I calibrated my G7. Do that for as many times until it reads correctly. Just my suggedtion. Or call Dexcom directly.

Have you tried calibrating? I did this once when the G7 was consistently showing lower sugars and that seemed to work.

Do you take acetaminophen?? This throws off cgm readings.

Your do understand that the sensor reads interstitial fluid not blood, correct? All sensors say to allow a 20% difference in readings from sensor to FS. I am on a insulin pump as well, so if it's over 20% difference, I go ahead and calibrate so I get the correct amount of insulin.
I have had where Dexcom had me calibrate every 15 minutes X3 to correct it. Now I just do that if it's wonky. I haven't had many issues with it happening, but last night was sensor change and I was up all night with a false low. Hoping it will straighten out.