Does a Ground plane in Eagle still need connections?
You've added ground plane (copper pour), and rat's nest connections from the pins to the copper pour disappeared.  That's intended.  That's how it should be.

If you zoom-in on on of the pins that are connected to ground (for example IC1 pin 8), you'll see spokes. That connect the via to the copper pour.  The spokes are created by the software, because the pin is connected to the same net as the copper pour.



By the way, every modern layout software behaves in a similar way (not only Eagle).