Nr Fairy,
I'm trying to picture this scenario. At what point did you switch off the governor? Any idea how? The governor will not work at lower than 80% RPM, and has an upper limit of 115%, above which it won't kick in. If it's winding up the RPM, and gets switched off during that, does it go above 115%? I don't know, but I suppose it's possible. Also, if you raise the collective at all, that'll bring up the RPM too, if the governor's off.
If you go through the whole thing more precisely, I'll see if I can work it out.