Might be unrelated, but here's another tidbit from Actiontec's FAQ:
Wi-Fi Miracast devices cannot simultaneously connect to ScreenBeam Receiver and Wi-Fi Router OR loss of Internet when connect Miracast device to ScreenBeam Receiver.
This is a limitation with some Miracast devices and is not an issue with ScreenBeam Receiver.
Some of the Miracast devices such as; LG Optimus G, Sony Xperia T, or Xperia TL, do not support simultaneous Wi-Fi and Wi-Fi Direct connections. ScreenBeam Receiver or Miracast connection requires the use of Wi-Fi Direct. The device will disconnect from the current Wi-Fi connection and vice versa.