I think figured out, with a lot oft testing, where it came form.
It is defiantly ACF Pro (no other Plugin, not from the templates, wp-config, functions.php)
On the most templates the wp default content-editor is deactivated and hidden by ACF.
Page-templates has the problem with revisions without the editor. When I activate the editor and add some content the revisions work normally.
CPT post don’t have this problem…
Is the any way to fix this problem?
