Sorry for late reply. I had numerous things that had priority over our website and am coming back to resolve some issues that I had.
The problem is apparently specific on Macs. I tried it on PC on Chrome and on IE (Edge and 11) and they work as expected while on Safari on Mac, it had issues rendering image banners with animated effets as shown on the video. I believe that few weeks back, the problem was present also on Chrome on Mac but that has been solved.
I tested to see if the problem is solved with the new Safari developper preview but apparently with the B2, the problem is still persistant.
I use a similar effect on another website with Dante installed and there is no problem on that one.