Since I got my P3P a couple weeks ago I have had very few connection issues - lightbridge or remote.  I have always assumed though that the telemtry (data relating to location, height, bearing, etc) was sent over the remote channel and not over lightbridge.  This would mean that even if the lightbridge went down completely I could still use the map in the app to get back home even if there was no video (assuming I did not want to use RTH).

Am I correct in that assumption?

No light bridge is a single 2 way tunnel, data is passed back and forth over this tunnel, this does not mean that it won't work when you loose video signal but the craft can still receive your signal, people have flown beyond loosing video for some time then RTH has activated once RC signal has dropped.
but it is one two way dupex carrier.