I suggest taking a look at your html sanitization settings make sure html isn't allowed in markdown settings.
Next step would be to move the other 2 topics from that category and check if you still see broken markup.
What's the preferred emoji plugin that works with 0.7.x? The URL generated seems to reference the
localhost:4567/plugins/, thus no image is rendered. This is a bit confusing because if I change the settings to domain.com:80 it works, but then I can't use nginx to proxy and cache for NodeBB.