I can confirm this here on XenForo with consistency each time I refresh the page. Oddly enough, I'm not able to produce this consistently on KH-Flare with the default style. Seems to be only here on XenForo.
It's only for a very short instant, so many will probably not even notice it.
Edit: Even the node icons and relative time don't load instantly.
In any case, yeah, I figured as such. Chrome isn't slower than Firefox, at least for me, but I have noticed it has a delay when there's a lot, if that makes sense, which seems contradictory, but not really. For example, it takes a while for the History page of an article on Wikipedia to load fully on Chrome. Like, you'll be able to see it, but not click anything.