Divi's big update introduced many changes; how it handles Google Fonts is one of them.
To make Divi (and themes based on Divi, like Extra) work with OMGF you'll have to disable the improve Google Fonts loading setting under Divi > Plugin Options > Performance.
Sidenote: there have been reports that the limit Google Fonts support for Legacy Browsers option also needs to be disabled, so I've added it here for full disclosure. In most cases, however, this shouldn't make any difference.
The Extra theme also offers the same features as Divi, the options to disable are located under Extra > General > Performance.