After awhile the chat windows begins to look like this:
Only after refreshing the window does the chat return to normal. Multiple people are reporting the same issue.
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Fixed now, after you press F5.
For the curious, the large hats used relative positioning to keep them aligned on the avatar, but the small ones incorrectly used absolute positioning, which means they relied on the position of the avatar in the page not changing. In a dynamic environment like a chat page, that's not a good thing to rely on.