HI Guys:
This is a matter of reference, Im speaking in terms of driver reading of the RPM. However, many systems are not pure in this sensing, sometimes a noise spike can occur and the system will run that section of code, this wont normally affect threading or your RPM display, as it is updated too fast for you to see , but that simple noise spike can make the program "think" that the RPM has slowed by 50% or more for just 1/25000th of a second, a fraction later the system will see the rpm is not really reduced.
Im pretty sure this is what caused the error, and weve fixed it so it will be out within a day or two I suspect, next version you see anyway will have the fix. Dont focus too highly on the 50% thing, internally its more than possibel for it to occur with no spindle slowdown that YOU see, but the driver may have seen several, it takes steps to reduce noise and youd enever see the slowdown.
thx
Art