Anyone else having "? ? ?" displayed on Dexcom G4 receiver + pump?

Here’s my maybe not so much of an issue but; I am past my “6m” battery life/warranty on my transmitter; going on month 8 now, and recently, for my last 2 sensor changes, they are coming up with ??? before my usual sensor change. P.S. I always wear my sensors for a full 2 weeks. I know some folks get longer wear time on theirs.
Has anyone else seen this kind of issue before their transmitter dies?

That sounds more like a sensor issue than a transmitter issue. When I start seeing a lot of ??? symbols, I know that my sensor is near the end of its life. I get well over 8 months from my transmitters (like pretty close to a year) - I have yet to see a replace transmitter/low/dead battery alarm.

Go into the settings on your Dexcom receiver, then choose device info. The third item down is the transmitter battery status. I’m also in my 8th month with this transmitter and my receiver is saying that the battery is “ok”. That’s the first thing I would check.

The "???"s sound more of a sensor issue, though, as @YogaO has mentioned. I usually have one really bad day during my second week of sensor wear, usually around day 10 or 11 of wearing it. If I can ride it out, it seems to straighten itself out. I just have to go without readings for several hours.

I agree that the ??? is likely to be sensor-related, not transmitter-related. I also re-start my sensors and have found some batch-variation in their lifespan. I average around 16 days out of a sensor, but the first three in my current batch have struggled to get past 14 days. In the batch before, 3 out of the 4 sensors made it past the 21 day mark.