Yellow status light - Manage ant+ simulator

What does the yellow status light next to an ANT sensor mean on the "manage ant+ sensors" screen? I have two varia lights. I can run my ConnectIQ app and connect to one of them. But after a day or so (with the light off) and the simulator off and not running, the next time I try to connect, the sensor just shows up with the yellow status light instead of gray or green. So then I turn on and pair to my other Varia. Same thing ... it works fine at first but eventually it switches over to this yellow status light instead of pairing. I then have to reboot my Mac and everything works great again. Is there a way to solve this problem without having to reboot my mac? It's super annoying b/c I have a bunch of services and virtual machines running on it and I have to restart all of them. Thanks for the info ... even just an indication of what the yellow light means would be great.