WordPress | Creating default object from empty value of line 639 wp-admin/includes/post.php

This time, a work colleague ( is a copyrighter ), notified me that, once he try to add a new post on our wordpress blog, he have an error;
Entering in a “Add post” mode, have an error on top of admin screen

Creating default object from empty value of line 639 wp-admin/includes/post.php

and he can’t see the “publish” button, but instead of this, he see a “Submit For Review” button, he show the content area only show as “text” mode, and, if he try to navigate to dashboard, can’t see plugins updates.

First thing that i try is to disable all plugins and switch to default theme ( Twenty Fifteen ), But nothing change.
Next thing, is to check for resources on our server, i had installed “All in one SEO pack ” that have a feature called “performance” that check system status.

But i can’t find something that tell me “hey guys we had find the problem..” …
So, last thing to try is to check the Database.

By googling i find a post that advise to check the “_post” table on our db.
Basically i solved by navigate to our PhpMyAdmin interface, click the “_post ” table, navigate to ” Structure ” then go to edit(change) ID.
Check the AI (auto increment), and save.
If AI is checked, deselect and re select it and save.

Back to our blog admin, all work fine, if i try to add a new post, i see the “update” button, and in the “Content area” can switch between “Visuale” and “text” mode.
If navigate to dashboard ( or plugins area ), can see and doing the updates.