Haha, yeah because the entire concept is new, it will take time for some to learn this new way of interacting and what it can do (Discovery is fun!) I personally love those moments of, "Oh wow, it can do that!?".
If they haven't already tell your co works to go to Settings > General > Accessibility > 3D Touch and set it to Light. It will make it so they do not have to press in as hard to trigger (peek and pop) because obviously they are having troubles not pressing hard enough, if they are just activating long press instead of peek on the home screen