astrosatch Yes, I tried with 1 second and it plate solved successfully.
Was the successful plate solve taken with a filter with a wider passband? The same exposure time may not work with a narrow band filter, depending on what region of the sky the OTA is pointed at.
But I think the root cause of the problem is that even though it says "Mount slews to target position", it never did. I believe that message is displayed right after ASIAIR sends the GOTO command at the second time parameter of the Meridian flip, and checked that the mount is no longer moving (finished the GOTO).
I do notice something weird in your screenshot that you had not mentioned in your original posting: the Current position is (22h,-20º), but the target of the flip is very far off at (0h, -26º). If the mount is good, and your polar alignment is spot on, the two coordinates should be precisely the same. I.e., a Meridian Flip does not change where the OTA is pointed to; it merely moves the OTA from the West of the pier to East of the pier. Note that the OTA should always be on the opposite side of the pier from the object it is pointed to.
Do you remember the local sidereal time (LST) when this error occurred?
It should be close to the "current" RA, (the Prime Meridian's RA is equal to the local sidereal time). If you remember what local time it was (to within 15 or 30 minutes) you can confirm with a planetary program like SkySafari, or with myriads of web calculators, what the Local Sidereal Time was. If you have SkySafari, the LST is in the Advanced window of the Dat and Time setup window.
The next thing to do is confirm with your planetary program to see if the equatorial coordinate (0h 53m, -26º 29') is above the horizon. As a quick sanity check, just compare -26º 29' with your local latitude -- it will quickly tell you if the Target is below the southern horizon (or more accurately, the Horizon Limit that you had set the Mount's hand controller to).
If the Target is below your mount's horizon limit, it is natural for it to refuse to execute the GOTO from ASIAIR (that is what a horizon limit setting is for). If the target is really below the horizon, what remains is to figure out why ASIAIR is using an odd target. For a Meridian Flip, the Target should be really close to the current position just before the Meridian flip.
So, there are at least two things that could be wrong, just given the screenshot above.
By the way, what Target were you shooting? And does it correspond to either the Target or the Current location in the screenshot?