'10TouaregTDI DEF Refill Warning On But Refilled 1000 miles ago?

My 2010Touareg TDI has 111,000 miles on it. I have refilled the DEF every 5,000 miles and have never received a refill warning. I refilled it at 110,000 with about 2 gallon of DEF, and now approximately 1000 miles later, I am getting a warning for DEF refill and that I have 450 miles left. Should i reset this? How do you reset it?

In checking the VAGCOM, I have a fault for 008319 Reductant Quality Performance P027F. When this fault occurred, the check engine light came on, the DEF refill icon and the message of 450 miles appeared. This same fault occurred maybe 10,000-ish miles ago with just the check engine light, and a top side removal of the remaining DEF and replacement with new fluid took care of the issue. The refill icon did not appear. I have heard that the fluid quality can expire and maybe that is what happened. Do you think the DEF icon refill is related? -no other related codes

Separately, I have had a lingering 008430 NOx Catalyst Bank 1 P20EE-001 Efficiency Too Low- Intermittent. This code shows up every 3000-4000 miles and I reset it as it is intermittent. It is also present but I have no reasons to think it is related. Does anyone know where the plug is for this sensor?- I want to hit it dielectric silicone and see if that resolves it or find out whether it is the sensor itself.

Finally, any thoughts as to whether I am really on a countdown to a no start? I need to be able to drive this vehicle but can't get to working on it until next week.

had a clogged DEF injector nozzle and clogged DEF injector line behind it. All good now. YMMV.

Take it in for free repair since under 120K miles. This is a warranty issue. The heater is toast. They will fit it with a new kit, takes 3hrs.