I've had the same problem, Bluetooth device was completely missing randomly after waking computer from sleep. Only shutdown + unplug brought it back.
Gigabyte support was of no use. Not a single useful advice.
I've decided to contact Intel support (I wasn't sure if it is bios/hw/driver issue).
They recommended to use Gigabyte drivers because they should be customized to the way Gigabyte integrated the adapter. Intel drivers are generic ones and may be not compatible.
So I've uninstalled Intel drivers and installed drivers from Gigabyte.
And the problem is gone.
Bluetooth device seems to be now always present after wake-up.