First of all, are you sure that all the fan headers are configured to use the CPU internal temperature sensor for their temp values? This is NOT the normal way to do things, and some mobos don't even give you that option. Most that do offer that option arrive pre-set by default to use the MOBO temperature sensor for the SYS_FAN headers, and that normally is the best choice.
Secondly, you should NOT set the minimum fan speed to 0% at the coldest. All fans have a minimum voltage or PWM setting to START them up, and a related minumum operating speed (set by voltage or PWM signal). If you feed the fan less than those minimum settings, the fan will stall and may not re-start. Normally the mobo will always start up all fans at 100% and then reduce to the required setting. The default mobo settings normally will not run the fans below 5 VDC in DC Mode, or about 30% in PWM Mode. But your custom "curve" tells it to reduce the fan signal to 0% PWM, so that certainly will stall the fan. THEN, as temperature increases, it will probably need to get up to a 40% to 50% signal at least just to re-START it. So, increase your minimum fan speed setting to 30% or more, and see if that solves your problem.