Hello @darrylr
If this is a production site you should still be able to use the WordPress Health Check & Troubleshooting Plugin as mentioned in my previous reply. This will allow you to safely, and only for your logged in admin user, to see and test the default theme ( along with disabling or enabling specific plugins, again just for your user ). For more information on how that works I would suggest reading the documentation which is also linked in my previous reply.
With that being said we’ve also tested this with the latest version of all 3 plugins and the latest version of Storefront and could not replicate the issue. Unfortunately, until we have more information to help us replicate the issue we won’t be able to formulate a patch. We apologize for any inconvenience this may have caused but hopefully using the above information regarding the WordPress Health Check plugin will give you more information on the root cause.
Once you know more please reply and provide further information on how we can replicate the issue you’re running into. Thanks for your patience, stay safe, and have a wonderful rest of your week!