Overview:

Child Object List views My Custom Object Filter Not Returning all results.

Example problem: The Account Plans object is a child object of Accounts. A User creates a new ListView in that custom object tab and selects My Account Plans as the filter type. The User clicks Save and views the results. Not all the Account Plan records, that the user created, are displaying.

Root Cause:

When the My Account Plans filter is selected, the OwnerId of the Account (the Parent object) is being used as the filtering criteria. Child objects do not have OwnerIds.

Solution: 

Thank you