Assuming that it is a CO2 tank and not nitrogen and that beer can be dispensed with the CO2, then CO2 has to be getting into the keg. Being that I doubt the laws of physics stop working in your kegs, it is just undercarbed. That would point to the regulator gauge reading high. I would suggest...
Ditto this for me. I just tapped a keg of Hefeweizen that used Wyeast 3068 and it has crazy banana smell and flavor. Ambient for me was 65-66 but the fermenter was a few degrees warmer. I can smell/taste the clove also, but the banana is definitely at the forefront.
I realize it has been a few months since this thread was active, but I wonder if the hangovers have improved with a little more aging of the wine? I tried my hand at a 5 gallon batch of EdWort's Apfelwein and I have been having similar problems. I didn't even use as much dextrose as the recipe...
It's doubtful that you screwed it up. Just wait another week and check again. It's probably on the low end of the temperature range for the yeast and it is taking a little longer.