First of all, thanks for your endless patience !
Looking at the output of the broweser console we have this TinyMCE:
majorVersion: “4”, minorVersion: “9.11”, releaseDate: “2020-07-13”
Doesn’t look very recent..
WP itself is the latest version (6.9.1)
Looking at the source of our admin page I identified two plugins that inserted extra css into the tinymce editor. I disabled them, now it looks like I have the pristine WP tinymce setup here.
I deleted the text block inquestion and re added it – no success.
