Customizr slider picture snapping into place

My pics are cropped to 1170×500 as described. When my pictures first slide into place it seems that they only fill up half the space and then quickly snap into place filling up the whole screen. After all the pictures run through once, the next time they come around they are fine. I really don’t get it. It seems to be worse the larger the screen resolution is.
Can anyone help?

Here is a video of what it looks like:
https://www.youtube.com/watch?v=XcGM5PMrDdU