Foundation folks, your "On This Page" sidebar in the documentation is busted in Safari 9.1.3. The sidebar is a Magellan object with Sticky behavior.
Symptom: after you scroll to the sticky trigger, the sidebar acts like it's absolutely positioned to the body instead of fixed; it jumps in from the edge of the page, overlapping page content.
Not seeing this bug in Firefox or Chrome. Haven't tested in IE.