Yes, it's webkit. The webpage isn't doing it any favors though. If webkit is trying to conserve memory and maintain speed it's not always recalculating the entire page, just what you are looking at. However if the webpage has incremental layout changes from expanding portions they can cause objects to overlap.
See in the middle of your screen (kind of behind other text) where it says 'Show More" on the site? Tap on that and it should "fix" it. If not find them all and tap show more.
While you are there tap on the square with lines under it on the left side of the address bar. Tap 'Report a problem with website'. Tap "Design is broken' then tap 'items are overlapped" then 'Report'.