After extensive testing I think I may have figured this out. The original developer of our site installed a custom plugin bundle that included the following individual plugins:
THESE DON’T WORK
– WPBakery Visual Composer – 4.3.5
– Templatera – 1.05
– Ultimate Addons for Visual Composer – 3.7.0
If I deactivate the original bundle it breaks out the individual plugins so I can disable them individually. If I disable the “Ultimate Addons for Visual Composer – 3.7.0” everything works as expected. As soon as I enable that plugin it breaks. I have purchased new versions of all these plugins and it seems to work.
THESE DO WORK
WPBakery Visual Composer – 4.9.2
Templatera – 1.1.9
Ultimate Addons for Visual Composer – 3.15.0
Hope this helps someone else.
-john