I checked availability before I called. BA had space available LHR-CPT per BA's site but no BA space MIA-LHR. AA wouldn't put us on either AA flight MIA-LHR or through CLT, PHL, JFK, etc. There was QR space from Europe (MAD, BCN, FRA, FCO, etc) to DOH then on to CPT. AA would not open space from MIA to any european city which QR had availability. The conversations were always cordial and professional but never got to an actual flight which could be booked. Looking at our reservation on QR website it currently shows us leaving DOH for CPT 9 hours before we arrive from MIA. There is a huge risk I was unaware of using an award ticket for a prepaid safari vacation and prepaid always a requirement as far as I can tell.
Last year we had booked SAA and LX to/from Zambia using UA miles. LX had a schedule change which caused a misconnect from the SAA flight. Within one day UA, yes UA, coordinated with LX and got space opened up on another flight which showed no FF availability. I'd think that's what "partners" do when they cause the problem.