UI Changes to Global Subscription Status

I am having a lot of issues with email deliverability because of changes to the Global Subscription Status on Customer Records.

They appear as UI events, with no other obvious field changes recorded in System Notes at the same time. When I have questioned some of the users, they were not even aware of this field, or where it is set, so I am confident they are no changing it intentionally (or even by accident).

I do not have any workflows that appear to be referencing that field.

My only thought is there is something else that can be changed/set in the UI (either on the Customer record, or possibly on another record linked to the customer) that results in a change of Status for the customer. Some of the examples have Sales Orders at the same time (so could be relevant) but I am also seeing these changes on Lead and Prospect records (although one of those had an LSA at a similar time, so maybe there is a related transaction change somewhere causing this)?