SOP's
The system behaviour is predicated on a general process which PBL uses the term SOP. He is not wrong in the literal sense, which is broader than the definition you may consider wholly from aircraft operations.
There are numerous examples of such mismatch of crew actions to the expectancies built into the design:
B744 off piste, midfield, NTAA. Crew miss one ATR mode change during the approach phase (ATR originally manual but engages in speed... with appr mode change), and then miss one thrust lever when going into reverse. ATR is managing to speed in the flare, ie increasing thrust.... until such time as disconnected by selection of reverse thrust on a thrust lever.
B744 off piste, end, VTBD. Multi crew inputs, decision changes and thrust levers advanced at touchdown, disarming A/B and SP/BRK's. Thrust lever again missed... "Fore...!"
Note these are TBC product events.
Same sort of issue (mismatches) occur with high ROC altitude captures, where the AP/FD captures a path that is established from a perceived energy state that exceeds the steady state energy capability of the system, results in odd ATR behaviour and as often as not, a minimum speed exceedence event.
SOP? At the system description level.
For the A320... in the flare, (without delving into the software code...) at some point the mode of the ATR needs to inhibit a response to low speed (then again... ). This could occur at the transition point for the flight control laws (pitch) or later at the trigger point for the thrust "retard", or even could have been achieved by a time delay and WOG sensing. All would work to some extent. reviewing flight data for the type would probably allow you to verify the laws... Or try the simulator for an indication (may be an approximation). The B737's logic we worked out from the THY bingle... if it wasn't already understood.
If the operator spends all of their time within the normal envelope, then the actual functioning of a system may be quite different to what is assumed, even after reading the available (limited by SBO) literature on the system behaviour. When things go pear shaped, the exact behaviour of the systems may not be identifiable in time by the operator, or provide adequate opportunity to rectify before cascading failures occur. Add task saturation, inattention/distraction/SA-I failures, then the number of excursions that occur on runways should hardly be a surprise given how we design and teach. Just add fatigue, water, (or other adverse stressors).