I followed the following process to see if it is your code with the bug.
1. On a Development box I set-up a base WordPress site and loaded the Evolve Pro theme.
2. I then created a home and blog page and set them as static.
3. I created a gallery post with a 3 grid across layout with 7 images all at 1240 x 850 original size .jpegs
4. I used a featured image.
5. I placed the flex post slider widget in a sidebar to display posts.
6. When you view the page you will see the css code bug.
7. I went one step further and added a posts slider to the blog page using Flex and then the css code not only showed up in the widget but also in the main Slider too.
I want to return these themes for a refund. I have spent to much time debugging and still have no end in site. Just so you know I have managed developers and their code for years as well as being a developer myself. I purchased your themes because I did not want to have to spend the time writing one myself. Standard WordPress functionality should work without having to debug, so for me your themes are not ready for prime time and I want to return these themes ASAP.