@GreyWind I think that has to do with communication or lack of. Some individuals have a higher level of intelligence and understanding while others struggle with simple social interactions and are incapable of connecting the dots and may even have trouble asking for one to rephrase your words in fear of looking foolish so instead they back off and pretend it never happened.
Sometimes it could be as simple as there wasn't anything to add to the conversation so they didn't. Occasionally, I am guilty of this. I am not fond of one liners and will find myself nodding in agreement to myself and moving on instead of simply saying/writing, "Agreed." To avoid becoming that of which I am not fond of.
It is quite discouraging though to be left in the dark and it can bring forth sadness because the connection was lost without knowing the reason behind it.