Child Custom Record Sublist is Empty in Edit Mode

Steps to Reproduce:
Create a custom record type which is a child of item records:
1. Navigate to Customization > Lists, Records, & Fields > Record Types > New.
2. Enter the Name of the custom record. (Ex. Item Child).
3. Check the Allow Child Record Editing checkbox.
4. Uncheck the Include Name Field check box.
5. Save.
6. Click New Field button on the Fields tab.
7. Enter a name in the Label field. (Ex. Item Field)
8. Set the Type to List/Record.
9. Select Item in the List/Record field.
10. Check the Record is Parent check box.
11. Save.
12. Click New Field button on the Fields tab.
13. Enter a name in the Label field. (Ex. Customer)
14. Select Customer in the List/Record field.
15. Check the Record is Parent check box.
16. Save.
17. Click the View Records link on the upper left portion of the page.
18. Click New button.
19. Enter value for Item Field.
20. Enter value in the Customer field.
21. Save.
22. Click the Item Field value.
23. Click the Custom tab.
24. Click Item Field tab.

Result: The custom record is listed.

25. Click Edit button on the item record.

Result: The custom record sublist is blank.

Solution:
1. Navigate to Customization > Lists, Records, & Fields > Record Types.
2. Edit the Item Child custom record type.
3. Click Customer field.
4. Check the Show In List check box.
5. Click Save.