Something isn't working right with the Heading on my site

Hi, as you can see here – http://polytowncoil.staging.wpengine.com/making-ms-house-part-1/ (hosted on WPengine) – all the headings in the article are looking the same but some are H2 and some are H3 and they shouldn’t be the same size…

Something is clearly not working right with the heading on the site and I can’t figure out why. I assume this happened after I updated the version recently as it was working OK before.

I also create a test post with all heading – http://polytowncoil.staging.wpengine.com/heading-test-post/ – and as you can see, they all look the same while this is how it looks on the backend of the post – http://screencast.com/t/lLQwQwZP3jv

Can you help me figure this out?