Once a user performs a pull-request, and a reviewer accepts this pull request, yet a second reviewer (or the first reviewer) declines it. The approval status of the reviewers is not reset.

Atleast the approval status of the person that declined it should be removed.

The result is now, that when a user re-opens a pull request after performing an update, all reviewers are still on approved and do not see the change in their inbox.

Nor does the pull request state that it was updated by the user by adding N commits.