with 3.8.9 and .10 inside Joomla 4.3.2. I am getting 0 Attempt to assign property "cssClassName" on array. This is with an update to php8 and the page is a pagebuilder page, and my stack trace is in the hidden area below, but the theme update also failed to live up to the promise of a one-click procedure, other pages have problems too.
UPDATE - All kinds of files were overwritten by the theme update that went with this (Konstra) so an all-around bit of a fustercluck. I am reverting the site. This methodology is not production ready.