In zhwiki, some Chinese characters will break the timeline, eg, "六"“八”.

Still happens on Russian wiki: "Timeline error. Could not store output files"
https://ru.wikipedia.org/wiki/%D0%A8%D0%B0%D0%B1%D0%BB%D0%BE%D0%BD:%D0%9E%D0%B1%D0%B8%D1%82%D0%B0%D0%B5%D0%BC%D1%8B%D0%B5_%D0%BE%D1%80%D0%B1%D0%B8%D1%82%D0%B0%D0%BB%D1%8C%D0%BD%D1%8B%D0%B5_%D1%81%D1%82%D0%B0%D0%BD%D1%86%D0%B8%D0%B8

Also happens on Chinese wiki, both <timeline> and {{#tag:timeline}} format code, will invoke “Timeline error: Cannot store output files." once edited. eg,

• https://zh.wikipedia.org/wiki/Template:%E9%95%B7%E5%BE%81%E7%B3%BB%E5%88%97%E9%81%8B%E8%BC%89%E7%81%AB%E7%AE%AD%E6%99%82%E9%96%93%E8%BB%B8
• https://zh.wikipedia.org/wiki/Template:%E7%A5%9E%E8%88%9F%E9%A3%9E%E8%88%B9%E6%97%B6%E9%97%B4%E7%BA%BF