I just noticed this answer that got bumped up recently on RPG SE. The editor was trying to replace a formerly MathJax-based table with one in Markdown, which is fine. But the table isn't working at all.
So, I hit Edit, and the live preview has the table just fine. Clearly, the server-side Markdown renderer and the client-side one for live preview, aren't matching up here.
For reference, here's the same exact table:
...blahblah |Magic Item Ingredients || |---|---| |Item Rarity | CR Range | |Common | 1—3 | |Uncommon | 4—8 | |Rare | 9—12 | |Very rare | 13—18 | |Legendary | 19+ |
I can confirm that the table above looks perfectly fine in the preview prior to submitting this report.
And after posting, it worked fine, until I added actual text in the blockquote, before the table, so that apparently has something to do with it.
Even if this broken table is okay, the two different renderers should probably be built to agree on the results, so people don't post things that look good in the preview, but are broken when actually displayed.