Maybe you should post a screenshot of the preview if it's a different symptom from what I described.

See this is preview image
Your table is too complicated with nested table insides which end up getting messy, plus the content
Automaticially nested tables are getting created.
I use only one table tag and then inside it TD's and TR's
But when I save and again see the code all TD's get there own table tag. (Magic.. is happening )