here is an excerpt from today’s Hakhel Organization’s email
HaRav Kanievsky continues by bringing the Rabbeinu Bechaya (end of ParshasVayechi) who writes that the reason the Asara Harugei Malchus were punished was because Yosef did not expressly state that he forgave them. It must be that the reason that they did not go to his Kever to ask for Mechila was because they did not realize that one must obtain express Mechila until they saw that they had been punished.