I'm experiencing the same problem on iOS. If i keep a finger on the screen and try to scroll gradually as I read, then it jitters. If I just scroll then release, read, scroll then release, etc. it is smooth.
Although Andrew (above) can replicate this, I haven't been able to. But I know it's not just you. Are there any other details you can give? Do other stories on the site do the same? What kind of iOS device do you have?
Sorry about this! It's the first we've heard of it and I wonder if it's something in this article.
EDIT: I just recreated it. It looks like a continually switching class causing the text to re-flow. I'm going to disable that JS temporarily while I figure out why it's flapping. Thanks for reporting it!
EDIT 2, 1:23PM Eastern US: I deployed a hotfix. We'll do a more permanent fix on Monday. If anyone else has trouble, let me know.
I'm experiencing the same problem on iOS. If i keep a finger on the screen and try to scroll gradually as I read, then it jitters. If I just scroll then release, read, scroll then release, etc. it is smooth.