This is happening to me a lot lately. It might be a side effect of having a 10Micron mount where it thinks it's accurately pointed to the center of a target, but it's slightly off. I have a target picked in the scheduler, and part of the initial setup is to slew to the target. It has taken 18 slew commands to move 1 arc second at a time to try and center the target. I don't suppose there is any way to nudge it to the center. The slew command to the target over and over isn't always working smoothly. This is especially the case after a meridian flip for some reason where the pointing model might not be as accurate on one side of the mount. But I don't know for sure.
The simplest thing may be to increase the tolerance to 40 arc secs. It looks as if the mount slew ends up about 30" in Ra away from the target. It could be because the mount firmware calculates the target position without allowing for the time the slew will take. The fial slew takes just ove 2 seconds so there's an error of just over 30".
not sure, only one way to find out. if you hover the cursor over the box for differential slewing it says it works better on some mounts, i.e. paramount if I remember correctly, so it might be worth trying to see if it helps