Magnus,

Very sorry about the issues you're having, and I appreciate you sending in logs and raising the issue.

I did look through the log, and it looks like the guider is doing what it should, e.g. it measures error and sends out the appropriate pulses to counter the error.
Unfortunately, it looks like the computed pulses are having no effect at all on the mount, as if it was not even connected.
Yes, very similar to what you said "as a Guide Assistant run in PHD2, that is, with no corrections sent to the mount".
In fact if you view the phdlogview output to the file you sent me, you can see that.