If I understand the php info page correctly i think opcache is disabled.
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I wonder if the update to php 7 will fix it when it comes out.
Im getting the errors generated all the time. Its particularly prevelant on hydrogen theme but even in the back end sometimes i get them. And it can show in one single template or module position too where the rest of the page loads which ive never seen before.
Happy to give you a super admin account to test if you wish. Reload one of my example pages on the site a few times it will generate an internal server error for you guaranteed