I know you are trying to be helpful but reproducing the error is maddening. It, of course, happens when I am actually imaging and then only some times. When I am imaging I don't want to take the time to deal with this, so I am trying to narrow down the situation with targeted tests. The driver does not appear to have its own logging. I'm not aware of any ASCOM system wide driver logging (other than profile and serial port). If there is such logging could you point me to it?
As I stated at the beginning there does appear to be strong evidence of SGP problems in that it does not time out on the filter change. Meanwhile, if Jared can give me some clues as to what SGP does during retry, I will carry on trying to reproduce the problem in a controlled environment (not under the night skies).