I think I found the problem. A mission goal requires several transports to be destroyed or departed. Unfortunately, one of them, Nandi, is loaded from mission Exile07 and sexp doesn't include situation where it's been destroyed back in that mission (so it never arrives in current mission). I suspect this is the case.
Noted for 1.2 patch.
A workaround: delete (or rename) file data/scripts/exile07ships and replay the mission without using a checkpoint, you should be able to advance.