I'm having the same issues.
iPhone7 using Safari. Logged in or not - makes no difference.
The main page opens okay, but once I go anywhere else ("active topics", for example), ANY scrolling is completely uncontrollable. Literally, the page jumps all over the place both up and down. No other way to describe it, really.
It's almost like when you have a regular html page with heavy ad content that keeps reformatting itself as the ads down the page continue to load while you're trying to read the content. Not sure it has anything to do with the ads (which are, as stated above, appearing between every thread).