I opened the site, changed tabs and left the page several times, but i never got this issue. Did you manage to fix it? If you still need our help, please send us your wp credentials in a private reply. So we can give it a closer look.
The problem is, when you change the window and then switch back you only see the running slide finish and then it stops. There is only the background picture left.
I checked your site, beside the fact that you have an old version of Visual Composer, and should update in order to avoid unnecessary issues, i don’t see any other problem.
As stated in my replies above, i don’t get the effect you are mentioning. I tested the site several times, switched back and forth, resized the page and still the slider run smoothly.
You can try clear cache and refresh page.
Check the layers out-effects and times at revolution slider. Make sure the layers don’t fade out before the slide is ended. Let us know if you need further help.
