I’m having the same problem. I noticed it started on several of my sites right after I updated to 4.3.
In visual composer, I edited one of my raw HTML blocks because I noticed a typo on my site. When I updated the page, my revision went through correctly and the results on my web page worked perfectly. However, I noticed another problem and when I went back to visual composer to edit the HTML block again, I noticed that half of my rows and columns were all missing.
I found out if you restore a previous revision, you can go back to where you could see everything in visual composer, but once you edit any block of raw HTML it causes the problem to happen again.
This is a major major problem for me, I hope wordpress can tune in here and help us out.
