The threshold for triggering a hard landing inspection is quite high in terms of g loading, though in many aeroplanes there are variable g limits based on roll rate etc on touchdown, so very difficult for the crews to identify if the landing they just did was actually a heavy landing.
Most reported hard landings are shown to have not exceeded that threshold, though that is usually after the fact when FOQA data is reviewed. The inspection having been done at the time in order to get the aeroplane moving again.
Again it isn't a huge surprise that a heavy landing report wasn't submitted as it needs to be a real bone crusher to actually be a heavy landing.
I am not privy to the details in this instance, nor trying to defend the actions of any party, just trying to point out that things are not as necessarily cut and dried as perhaps some people may like to believe.