I've got my solar lipo charger and mintyboost working and I'm happy as a clam. I just went back and scraped off the traces from the therm resistor and soldered on the thermistor.
So here's the question... I tested it with a cold pad and the DONE LED came on. The PWR and CHRG LEDs stayed on. When I took it away from the pad it warmed up and the DONE LED went off. Is the DONE LED coming on what you mean by "The charger should stop charging the battery?" It seems to make sense. but I wanted to make sure.
By the way, I'm a lousy solderer, but even so, the Mintyboost seems to be very sensitive to bad soldering. I noticed people posting a lot of questions particularly around the data lines and it took me a couple of tries to get it right.
Nice product and it does my charge my B&N Nook Tablet.