Wikimedia Bugzilla is closed!

Minimal test case:

{|
|-
| align=left colspan=3|'''Valid Votes'''||'''38,847''||'''100.00%'''
|}


Note that the bolding of 38,847 is not closed correctly: one quote is missing.

The PHP parser renders this (correctly) as:
<td><b>Valid Votes</b></td><td>'<i>Valid Votes</i></td><td><b>100.00%</b></td>

Parsoid renders this in an ... interesting way:
<td>'<i>Valid Votes<b></b></i></td>38,847</td><td><b>100.00%</b></td>

Note the stray quote before Valid Votes, the fact that Valid Votes is now in italic, the empty <b> tag, and the fact that 38,847 is completely unformatted.

Because the output HTML is so weird, this obviously doesn't round-trip right either:

| align="left" colspan="3" |'''Valid Votes''''''''||38,847||'''100.00%'''

The real-world test case that brought this to my attention is http://parsoid.wmflabs.org/_rt/en/Wellawatte-Galkissa_Electoral_District?oldid=377319087