"Failure when converting editor format to storage format" with user mentions

<table class="wysiwyg-macro" style="background-image: url('http://macmini.local:1990/confluence/plugins/servlet/confluence/placeholder/macro-heading?definition=e2RldGFpbHN9&amp;locale=en_GB&amp;version=2'); background-repeat: no-repeat;" data-macro-name="details" data-macro-body-type="RICH_TEXT"><tbody><tr><td class="wysiwyg-macro-body"><table class="confluenceTable"><tbody><tr><th class="confluenceTh">Target release</th><td class="confluenceTd"><pre class="text-placeholder">Release name or number</pre></td></tr><tr><th class="confluenceTh">Theme</th><td class="confluenceTd"><pre class="text-placeholder">Roadmap focus area</pre></td></tr><tr><th class="confluenceTh">Document status</th><td class="confluenceTd"><img class="editor-inline-macro" height="18" width="88" src="http://macmini.local:1990/confluence/plugins/servlet/status-macro/placeholder?title=DRAFT" data-macro-name="status" data-macro-parameters="title=DRAFT"></td></tr><tr><th class="confluenceTh">Document owner</th><td class="confluenceTd"><pre class="text-placeholder" data-placeholder-type="mention">Person responsible</pre></td></tr><tr><th class="confluenceTh">Designer</th><td class="confluenceTd"><pre class="text-placeholder" data-placeholder-type="mention">Lead designer</pre></td></tr><tr><th class="confluenceTh">Developers</th><td class="confluenceTd"><a class="confluence-link" data-base-url="http://macmini.local:1990/confluence" data-linked-resource-id="950274" data-linked-resource-type="userinfo" href="http://macmini.local:1990/confluence/display/~shannon" data-linked-resource-default-alias="Shannon Krebs">Shannon Krebs</a></td></tr><tr><th class="confluenceTh">QA</th><td class="confluenceTd"><pre class="text-placeholder" data-placeholder-type="mention">Lead tester</pre></td></tr></tbody></table></td></tr></tbody></table><h2>Goals</h2><ul><li><pre class="text-placeholder">E.g. Simplify the user experience, reduce friction etc...</pre></li></ul><h2>Background and strategic fit</h2><pre class="text-placeholder">Why are you doing this? How does this relate to your overall product strategy?</pre><h2>Assumptions</h2><ul><li><pre class="text-placeholder">List the assumptions you have such as user, technical or other business assumptions. (e.g. users will primarily access this feature from a tablet).</pre></li></ul><h2>Requirements</h2><table class="confluenceTable"><tbody><tr><th class="confluenceTh">#</th><th class="confluenceTh">User Story Title</th><th class="confluenceTh">User Story Description</th><th class="confluenceTh">Priority</th><th class="confluenceTh">Notes</th></tr><tr><td class="confluenceTd">1</td><td class="confluenceTd"><pre class="text-placeholder">Short identifier for the story</pre></td><td class="confluenceTd"><pre class="text-placeholder">Describe the user and what they are trying to achieve</pre></td><td class="confluenceTd"><pre class="text-placeholder">Must Have</pre></td><td class="confluenceTd"><ul><li><pre class="text-placeholder">Additional considerations or noteworthy references (links, issues)</pre></li></ul></td></tr><tr><td class="confluenceTd">&nbsp;</td><td class="confluenceTd">&nbsp;</td><td class="confluenceTd">&nbsp;</td><td class="confluenceTd">&nbsp;</td><td class="confluenceTd">&nbsp;</td></tr></tbody></table><h2>User interaction and design</h2><pre class="text-placeholder">Include any mockups, diagrams or visual designs relating to these requirements.</pre><h2>Questions</h2><p>Below is a list of questions to be addressed as a result of this requirements document:</p><table class="confluenceTable"><tbody><tr><th class="confluenceTh">Question</th><th class="confluenceTh">Outcome</th></tr><tr><td class="confluenceTd"><pre class="text-placeholder">(e.g. How we make users more aware of this feature?)</pre></td><td class="confluenceTd"><pre class="text-placeholder">Communicate the decision reached</pre></td></tr></tbody></table><h2>Not Doing</h2><ul><li><pre class="text-placeholder">List the features discussed which are out of scope or might be revisited in a later release.</pre></li></ul>