The occurs due to obsolete waypoints script loaded by Visual Composer. We use the same scripts handle ‘waypoints’ as VC to load our waypoints script and hence only one of the waypoints script instances are loaded into the page depending on who gets called first. This helps avoid loading the same script twice. Since VC loads a very old version of waypoints (2.0.2 – current is 4.0.2), the animation fails.
If you disable VC, the animation works fine. Pls contact VC support and ask them to update their libraries. Their isotope library is another one which has not been updated for ages now (still 2.0.2 and current is 4.x). Best is move away from them completely, IMO since their developers are slowly replacing VC with a brand new plugin.