Varia 715 Rct not showing speed of me or on coming cars on video overlay

Same.  Mine use to as well. I was loaned a Varia Vue from my LBS to test. When I went to setup the Varia Vue I saw there was an update for my 715 so I did it.  Ever since the update I no longer have this data.  Also updated my 1050. Not sure which update broke this metric but hopefully a dev sees this and can fix it in a new update next time.

I only bought mine and when i switched it on it asked me to update and i did so did not see it work on older Firmware 

The Varia app says you need a compatible Garmin device or phone. Are you riding with one of those and have them connected to the RCT715? I guess you have to share your location too with the app if you are using your phone.

They don't have a built in GPS

I have mine paired to my Edge 1050.  It showed speed and GPS date last week.  It stopped when I updated my Edge and Varia last week.  

You talking about the Varia app gave me an idea.....I always use my Edge 1050 but decide to actually open the Varia app. The app has some more settings  in there that don't show on the Edge 1050.  GPS and Speed overlay were set to off. I turned them back on.  They must of defaulted to off when I did the update. 

Should all work again on my next ride with my Edge 1050.

I have tried both and the 2 together no difference

yes they are both switched on in the app turned off and on again no difference

interesting..

Do you see that location arrow thing that the Android or iOS shows when location is being shared by the app? If not your phone might be blocking location sharing??

No location is set to on in app settings