🐛 | CKEditor 5 - Font Plugin (Text Color, Background Color) | Error after installing CKEditor 5 - Font Plugin (bis)
The patch worked for me too.
It solves also another issue I ran into: On a fresh install, I was not able to add font colors. the "Add" button would simply not react at all. After installing the patch and saving an empty configuration, I can now add colors.
I suspect that maybe the JS eventListener does not get attached to that button before the first save (see the editor.js file).