What is the MCT at LHR? I've got an LHR-SFO-LHR booked and am changing the dates. On the return leg, the change screen is showing this as the shortest connection:



But, there are two earlier flights (shown here if I try to book standalone):



Is this an MCT thing or something else?

The booking was Premium Economy (W) upgraded to business with cash (fare difference). MMB is showing the CW leg in class R and the domestic leg in J.