I have not modified the core in a way that would affect this behaviour.
I am sorry, I do not follow you. Are you saying there is a valid reason why I am not seeing those in the "My updates"?
In your first answer you said:"it is just a list of questions in which you have taken some action: adding a comment, answering, favoriting, etc."
So I presented a list of questions that user vbaskos was somehow involved, but they do not appear in the "My Updates" of user vbaskos.