it’s odd that a system that would fail at Mach 1.02 is judged fully competent, with margin, at Mach 1.4.
I think you will find that the dynamic surface pressure on the aircraft control surfaces under maximum thrust at Mach 1.02 would have been considerably higher than at a higher altitude at Mach 1.4 and where the scenario may also have been in a re-entry state, i.e. reduced thrust.