Contact/Customer and Case Records > Messages Sublist View > Changing the View in the Case Record will Change the Messages View in the Contact Record

To resolve, customize the sublist default view for both record types. For the Contact record and the Case record.

Steps:

1. View a Contact record under Lists > Relationships > Contacts. 
2. Navigate to the  Communication tab, then click Messages.
3. Under Messages subtab, choose View = Default.
4. Click Customize View.
5. Customize as needed.
6. Click Save.
7. Navigate to Communication tab of a Contact record > click Messages > user sees View = the custom sublist view user created is selected.
8. View a Case record under Lists > Support > Cases. 
Note: Pick a Case which is saved under the Contact record used above.

9. Communication tab , then click Messages subtab.
10. Choose View = Default.
11. Click Customize View.
12. Customize the message list as desired.
13. Click Save.
14. Navigate to Communication tab, then click Messages > user sees View = CASE -Custom Message Default Sublist View.

15. View the Contact record
16. Refresh the page.
17. Navigate to Communication tab, then click Messages.

Actual result: The message sublist under the Contact record remained unchanged.