PCIe6612: Inverted PWM duty cycle reported by PWM measurement.

Hello,

Using the NI API, I have output a PWM signal which I then measure with another counter on the same card.  Works fine.  Without too much effort, I can introduce a disturbance such as disconnecting and then reconnecting the running PWM signal.  This disturbance causes the PWM measurement to report an inverted duty cycle.  An external oscilloscope will show a 20% duty cycle, the NI API will return and 80% duty cycle.  I can then change the duty cycle on the fly to 70%.  The oscilloscope will show a 70% duty cycle, but the NI API will return and 30% duty cycle.  Any way to stop this or recognize that it is happening in the software?

Thanks for any info.