Pushed out an update to the Members FORK plugin that I'm maintaining that fixes the issue of the Gutenberg/Block Editor implementation of the Widget area. I also pushed the fix to the developers/maintainers of the original Members plugin (saw they pushed out the update as well). Now you will have no problems using the permissions/control metabox in both the block editor and/or traditional WordPress editor areas.
You can grab the update automatically in your WordPress Admin dashboards and/or download it from your WPStudio account.
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