I would like to ask about two types of problems. One seems to be a bug, the other one - not.
When I started using MSE I always receive notifications in my inbox about comments on my questions, comments on my answer and that there is a new answer on my question. Unfortunately, some of these notifications do not appear now in my inbox. As an example, when joriki answered my question Bounds on random walk with a negative drift nothing happened in my inbox, I eventually read the answer and then checked inbox - it was empty.
I never received notifications that the answer on my question was edited, so I guess that such notification in not provided on MSE. Since sometimes people add details/extend their answers even without the request of OP, won't it be useful to notify OP also that the answer on his question was edited?