I’ve finally tracked down the cause of this. It broke on 6th Jan, after this commit by @zogstrip
My iframe already has a fixed height, defined in pixels like this
<iframe src="http://discourse-test.taylorhq.co.uk/embed.html" frameborder="0" width="100%" height="250"> </iframe>
The commit above added checks that data[:height] exists before accepting a ‘rich’ onebox… however, it’s not pulling that height from the parsed HTML, it’s trying to get it from the oembed JSON file. @zogstrip is this expected behaviour? Should I be defining the height of the iframe in the oembed JSON?