I have Flash disabled but noticed SOME of the video HTML5 ads (mix of them not one) are hanging Chrome for about 10-20 secs - NEVER seeing this on any other site. Normally it's when I'm running other apps and come back and the HTML5 ad tries to replay. Something isnt' right in that HTML5 ad object you are using

Chrome Version 61.0.3163.100 (Official Build) (64-bit)
Mac OS 10.13

If I use Chrome's Task Switcher it will show for an idle FT page with nothing happening 140-160% CPU usage (Multicore system). I see no on screen video playing and the scroll keys/trackpad don't respond. 30 sec later it's fine. Not seeing this on other site HTML5 ads or auto video play