Title column group changed from "Custom Columns" to "_Hidden" after deployment of Design Package

Using design manager >> export solution (Master Page/Page Layouts/Style library >> Our Code) >> generate Design Package WSP & download it. 

Now, Import Design Package WSP into a new site collection . After import done, We are trying to create new list (Custom or Issues) in the site collection. Title Column property Group="_Hidden" instead of "Custom Columns".

This is happening after first week of October-2016 in SharePoint Online(Office 365).

Any Idea why it changed the group?

G Goyal