My poor, addled brain is about to give up on formulating a OWE fare. I thought I followed all the rules, but my TA has been informed by BA that it doesn't meet the rules. I have about a week to rework this before my TA is back in town and I have no idea what the problem is. Any of you folks see what the issue could be?

BOS-MIA-MVD (STOPOVER)
MVD-SCL (STOPOVER)
SCL-GRU (STOPOVER)
GRU-SCL-LAX-HKG-LHR-NAIROBI (STOPOVER, PHEW, FINALLY!)
(NBO-ENTEBBE/KAMPALA via SIDE-TICKET)
EBB-LHR-BOS

I thought this was simple enough and the two intercontinental arrivals/departures in both the US and LHR fit the requirements in each case, as they're connecting directly to onward out-of-continent flights.

I'd greatly appreciate any insight, as always.