The compability flag "enableDuplicateSassImportsFix" has been removed from the theme configuration causing the fix to be enabled by default. If you have utilized the flag in your theme configuration and set it to "true" you can safely remove it. if you have not utilized the flag or set it to "false" please be aware that every SASS files is now again only included once in a theme build (as intended).

(CMS-21703)