When an editor tried to remove a heading, the following empty h3 tag seems to have been left behind: <h3 data-parsoid='{"dsr":[4514,4534,3,3]}'></h3>
Serializes to ===<nowiki/>=== and the user complained about it.
From the bug report: /mng/bugs/en.2013-06-10T16:41:02.032Z-Lightning_(software) on parsoid.wmflabs.org
Version: unspecified
Severity: enhancement