Color Theme Changes After Submitting a Support Case via Web Store My Account

This happenswhen an online case form is used instead of the standard case form (external)via My Account.
 

To reproducethe problem:

1. Set Web Store Color Theme = Purple and Gray
2. Set custom online case form as Support Caseform for My Account/Customer Center. Navigate to Setup> Support > Support Preferences > External tab > DefaultCustomer Center Case Form
3. Shopper goes to the Web Store > My Account> logs in and clicks on See SupportCases > New
4. Shopper fills in details then submit or hit theBack browser button
5. Notice that color theme changes frompurple/gray to a standard color theme.
6. Color theme would be applied only after userlogs out and logs back in
 
To resolve:
 
Make sure same color theme for Web is applied tothe custom online case form. 
Navigate to Setup > Support > Online Case Form > edit Case Form > under Set UpAppearance > set Color Theme.