While looking at Japanese SO's Python chatroom feeds, I realized that the ticker feeds doesn't display the feed's title correctly.
New items from these feeds will be shown via a slide-down ticker overlay that periodically appears at the top of the room, and will not be persisted.
After checking the feed, the problem was identified due to the title containing Japanese characters:
<title type="text">python タグが付けられた最新の質問 - スタック・オーバーフロー</title>
I have also tried to change the encoding to Unicode (UTF-8), Japanese (Shift_JIS, EUC-JP, ISO-2022-JP), and Western (Windows-1252), but nothing changed.
With this, I assume the problem is related to title conversion from the feed to ticker feeds.
Tested on: Chrome 40, FireFox 36 & IE 11 on Windows 7, so I doubt it's browser-dependent.