When connecting to ForeFlight with the IFD and an ADS-B input, ForeFlight will recognize two devices (Avidyne IFD and ADS-B). Users seem to be experiencing altitude / GPS problems because in some cases, ForeFlight will use the ADSB stream as the default GPS position as opposed to the IFD GPS data, which is more accurate.  To fix the problem:

1. On ForeFlight, go to More > Devices > ADS-B.

2. At the bottom there should be a slider that says "Use as GPS" - make sure this is turned OFF.

This should fix the problem where the traffic altitude is wrong and a glide ring is not shown.

When corrected, in the instrument panel on ForeFlight, there should be "(IFD)" after "Accuracy" indicating the IFD's GPS position is being used. See below:

Here are screenshots of the steps to fix the GPS source bug. I would think many users could face this problem.

Traffic altitudes are way wrong and GPS accuracy is terrible (in red).

Under More > Devices > ADS-B you can see the last option "Use As GPS" is on. This needs to be turned OFF to get correct GPS information.

Now you can see that traffic altitudes are correct and GPS accuracy is green and has "(IFD)" next to it.

This setting is persisted, so users should only have to turn that slider off once and never have to touch it again.