Inactive Custom Record entries are still available when Parent record is edited.

1. Login as Administrator.
2. Navigate to Setup > Customization > Record types > New
3. Create a custom record set Records are Ordered and Allow Inline Editing
4. Click Save.
5. Add a new field.
6. Enter a Name.
7. Set Type as  List/Record.
8. Set Store Value is True.
9. Set Record is Parent is True.
10. Click Save.
11. Open a customer record and create a new custom record entry.
12. Set Inactive.
13. Click Save.
14. Edit the customer record and the custom record entry is still there even if Inactive.

To remove all Inactive custom record entries from the Parent Record, Records are Ordered and Allow Inline Editing should be unchecked.