Why is the owner field on the Approval and Approval Vote Tracking tables set to email (OwnerEmail) instead of owner like all other tables?
This is due to how approvals are processed in terms of email automation.
"Approve My Vote" and "Deny My Vote" not working in Change
"Approve My Vote" and "Deny My Vote" not working in 2014.2 or later release. This is due to change in Owner field's stored value to email address from LoginId.
In both Quick Actions, there is a Child Object Filter. Expression in the filter need to be changed to "$(Owner==CurrentUserEmail()) " since store value is changed to email address. Here is a screenshot.