When I recently updated to Version 3.5.2 – I noticed that my Vimeo and Youtube embeds no longer scale down responsively – it just stays the same size and lays on top of other elements on a smartphone and tablet or if you just squash the window down. I have a premium Vimeo account so these should be great on an iphone.
It worked great (before the upgrade) for Vimeo and Youtube in previous versions but I could never make it work for a self-hosted h264 video with HTML5 embed code.
This is the code that used to work perfectly for Vimeo…