Hi,
Same problem for me.
When editing, the Visual Editor is empty, switch to Text Editor then back to Visual Editor to display content works.
But update content using the visual editor fails, then the changes in the text are well done. It seems that the visual editor is in conflict with Yoast SEO.
Moreover, this problem appears whatever the theme as it occurs with the Twenty Sixteen theme and WordPress 4.5.
Hope to see a fix soon.