As always please check this with plugins disabled. Also please note that it sounds like you are experiencing different issues.
For Sneakyman it sounds like you have this problem https://theme-fusion.com/forums/topic/impossible-to-update-a-post-or-page-after-update-avada-5-5-2/ Which will be due to a plugin and the new WP version (not Avada update as keeps being mentioned)
For docedesign that sounds like a PHP or JS error. Again most likely a plugin or in Fusion Builder > Settings not having the builder enabled for all post types.