You are correct that in a manual start the FADEC does not auto-abort.
However it still passively monitors the engine.
The grey background will disappear once the engine is stabilised with : Ingition off, Start valve crossline, idle parameters normal.
Even in the manual start sequence, the FADEC still controls the above (ignition, start valve).
Ref: FCOM 1.70.20 P3, FCOM 3.04.70 P5