The prev link (i.e. here) for the last entry at https://zh.wikipedia.org/w/index.php?title=User_talk:Gakmo&action=history displays only an error message.
Error An error has occurred while processing HTML/wikitext conversion. Return to Wikipedia:首页. [306620c6] 2015-10-26 22:44:49: Fatal exception of type "Flow\Exception\WikitextException"
2015-10-26 22:44:49 mw1258 zhwiki exception ERROR: [306620c6] /w/index.php?title=User_talk:Gakmo&action=compare-header-revisions&header_newRevision=sr2oxcnfxi5ca9x9 Flow\Exception\WikitextException from line 143 of /srv/mediawiki/php-1.27.0-wmf.3/extensions/Flow/includes/Parsoid/Utils.php: Conversion from 'html' to 'wikitext' was requested, but core's Parser only supports 'wikitext' to 'html' conversion {"exception_id":"306620c6"}
Clicking "Edit description" at https://zh.wikipedia.org/wiki/User_talk:Gakmo
shows this content in the text-area: Due to a technical error, this post could not be retrieved.
(But in read-view it shows this as the content: 既往讨论已于2015-10-19存档在User talk:Gakmo/存档 1。)
Gakmo reported the bug at https://www.mediawiki.org/wiki/Topic:Srahmurfaimvrnnm saying:
I tried to edit description on my talk page (zh:User talk:Gakmo) but encountered error message when I want to edit the wikitext saying Parsoid error. When I want to save, the message below appeared. How can I fix it? Many thanks.
[404f2474] Exception Caught: Conversion from 'html' to 'wikitext' was requested, but core's Parser only supports 'wikitext' to 'html' conversion