You can see that your Rx1 frames were very high and the dropped to 0. However this happened at the same time that your Tx frames dropped to from ~95 to 50.
Later your Tx frames when up back to 98, and at that same time, your Rx1 frames came back from 0 to 100.

I don't think your Rx1 frames really went to 0 at all. It seems to me your transmitter module did not receive the information from the receiver and that why it was showing 0, when in reality Rx1 was always very good (90-100).

Weatronic transmits a weaker signal from the receiver to the Tx, because it only uses one antenna for that. Typically this will happen to me for a few seconds. Yours lasted too long. Maybe antenna #1 is being blocked? Try changing its position.
I doubt your plane was at risk.

If you want more opinions, you should post in the other thread that I mentioned in my previous response. There are some good experts there.
Good luck