RMC Control - Not triggering email notification

Summary:

We have created a control model in RMC that is scheduled to run regularly. Recently, we noticed that it has picked up four new incidents, but the assigned resolvers did not receive any email notifications. Under Settings for Email Alerts and Notifications, we have a few objects with email and notification setups. I tried to add Transaction Control, but it does not appear as an option. However, if I navigate to Mass Edit Security Assignment > Select Object, Transaction Control appears on the list.

Additionally, the business has noted that emails and notifications have not worked for any of our controls. Is there anything we are missing?