What is the expected behaviour of 2 unset priority datasources?

According to https://unifysolutions.jira.com/wiki/display/IDBPLUS51/Priority, data sources with unset priority are considered lowest priority.

Based on that, what is the expected behavior of an attribute in an adapter which has only 2 data sources, both of which are unset priority?

In this example, Person is a locker and Active Directory Person is a bidirectional link between the active directory adapter (the screen this screenshot was taken from) and the Person locker.

In the case of the attribute being changed in the source system and coming into the adapter through the connector: will it override what's already in there from person, or will it thrown away and have the data from the Person locker push back out to the connector?

Thanks,