It’s because ajax loading which bypasses the row styles added with Visual Composer in row design options or other plugins within the content.
To take advantage of the nice inline loading effect, as a step-by-step guide:
A. press Classic Mode Visual composer button
B. you will see a bunch of .vc_custom_.... codes
C. copy them
D. open the raw html at the bottom of the posts content
E. Paste it there inside
That's all.
If you don't want to bother with these styles set 'Load Slides Content With Ajax' to 'No' in showcase page options