Or it may just be this....
Using chrome? started happening with a bunch of different sites recently. Their advice is to use their new developer browser called google chrome canary.
https://productforums.google.com/forum/#!topic/chrome/zDMRJoAHtNcCouple other suggestions here, but they don't work. Canary seems to be working fine so far, haven't had the scroll lock up since I installed it.
https://www.google.com/chrome/browser/canary.html - here's the download link.
It's not a cache issue, or an extension issue, it's something that went wrong with the last chrome update. But their new canary browser is more up to date and it doesn't affect it.