This is a confirmed WordPress core bug:https://core.trac.wordpress.org/ticket/42574. “MediaElement upgrade causing JS errors when certain languages are in use e.g de_DE-formal”.
The issue applies to any language file in this format: de_DE-formal.
To resolve this, change the WordPress Core to the regular format: de_DE by changing the language in the WordPress admin area (Settings > General). For example, if currently set to “Deutsch (Sie)” instead select “Deutsch”.
Comments
This is a confirmed WordPress core bug:https://core.trac.wordpress.org/ticket/42574. “MediaElement upgrade causing JS errors when certain languages are in use e.g de_DE-formal”.
The issue applies to any language file in this format: de_DE-formal.
To resolve this, change the WordPress Core to the regular format: de_DE by changing the language in the WordPress admin area (Settings > General). For example, if currently set to “Deutsch (Sie)” instead select “Deutsch”.
Best regards,
Muffin Group team