I'm using Exec-PHP along with the Digg Digg social sharing plugin. I manually insert the php for Digg Digg into my posts.
It works fine on any post that doesn't contain <!--more-->. However, as soon as that code goes into the post, Digg Digg returns raw php.
I'm awaiting a response from Digg Digg's developers, but wanted to see if there's the potential for this problem within Exec-PHP.