When I am using the forum when viewing a forum post, the page scrolls up by itself a small amount every 3 seconds. Since other forum pages work OK, it might have something to do with the thread tools - for example for this post, scrolling doesn't occur. It only seems to occur when the thread tools bar is active at the bottom of the page.

Thread example - any, so here is just a random thread:
http://www.flyertalk.com/forum/briti...k-staffer.html

Here is an example of what happens. Screenshot 1 is of the forum post, Screenshot 2 is 12 seconds later, as the page jerks up a tiny amount every 3 seconds.
http://imgur.com/a/ipjo6

I disabled my Adblocker program (and will keep it disabled to support the site), but this has not resolved the issue. I don't have any problems viewing other websites, and I do not use many additional plugins.

Since you don't have any other reports it is probably a problem unique to me, but could you test it anyway?

Browser: Google Chrome Version 56.0.2924.87

When testing in IE, the problem didn't happen.