Trying to change and ex-CAI (now an exDOH) DONE5 first segment has already been flown. I'm aware the below itin will become a DONE6 hence the earlier question about historical pricing. This is ticketed through a TA. Is the following a valid itin:

DOH-MIA-SCL-MEL-PER-HKG-CTS-HKG-MLE-HKG-JNB-xDOH-NBO-xLHR-KEF-HEL-DOH

TA says the JNB-DOH-NBO sector is not permitted. Aren't I allowed a second intercontinental departure from DOH provided it is only a transit? Or is that not allowed from Africa? I can never read that rule clearly. Thanks for your input.