@FlightDetent; All Airbus FCOM says about the red Autoland light in relation to the flare, is that it will illuminate if the FMGS detects a "long flare":
FCOM PRO-NOR-SRP-01-70 Warnings for ILS/GLS Approach.
No definition is given about how it decides what a 'long flare' actually is, but it does NOT say that it will illuminate if there is no flare.