Consider this wikitext:
{|
|x
|| <code>bold=yes<wbr/>|code=yes</code>
|}
{{1x|1=
{{{!}}
{{!}}x
{{!}}{{!}} <code>bold=yes<wbr/>{{!}}code=yes</code>
{{!}}}
}}Parsoid's wt2htmls emit this (normalized to remove unnecessary attributes):
<table>
<tbody><tr><td>x</td>
<td><code>bold=yes<wbr/>|code=yes</code></td></tr>
</tbody></table>
<span about="#mwt1" typeof="mw:Transclusion" data-parsoid='{"pi":[[{"k":"1","named":true,"spc":["","","\n","\n"]}]],"dsr":[50,133,null,null]}' data-mw='{"parts":[{"template":{"target":{"wt":"1x","href":"./Template:1x"},"params":{"1":{"wt":"{{{!}}\n{{!}}x\n{{!}}{{!}} <code>bold=yes<wbr/>{{!}}code=yes</code>\n{{!}}}"}},"i":0}}]}'>
</span><table about="#mwt1">
<tbody><tr><td>x</td>
<td>code=yes</td></tr>
</tbody></table>So, tablefixups is treating the content before the | as attributes incorrectly.