I'm having this strange issue on a website I'm working on using a modified Wordpress Twenty Sixteen theme: http://olderbeast.com/
It looks fine on Chrome and Opera, but on Firefox and Edge the blog feed ignores the new header image and overlaps it at the top. I believe this is due to the float: left that the div#primary has, but I've tried multiple clearfixes and nothing has changed.
Am I missing something, or not implementing clearfix properly?
EDIT: Michael Coker solved it with making the image display:block and clear:both. Thanks!