Embedded Youtube thumbnail does not show up on category stream

Select normal textarea option for that editor field. It should work.

Check the screenshot:
https://www.awesomescreenshot.com/image/1532868/04acdbaba475dc31a545582d90340d3b

Thanks for the reply. The form was already on Normal, but the problem persists.

I also just realized that after submitting the post, in the final post page, it shows the post title, post author and post date, but no post category.. strange?

This is my problem as well.