Carlos Saenz

Yep, it was the Easy Foundation Shortcodes plugin. That plugin is also incompatible with Foundation based themes, like FoundationPress, because it contains its own entire copy (which conflicts with) of Foundation.css!!

I’ve notified the plug-in author here:
https://ww.wp.xz.cn/support/topic/this-plugin-is-incompatible-with-foundationpress-and-breaks-xmlrpcphp?replies=1

Thanks so much,
Carlos