Hi! get same thing on MP 1.3.48 latest beta. Switched to beta because latest stable doesn't work with joystick - strangest shit, but what ever.
I have my signal strangth wonder between 26-29% Pixhack-v3 -> Pi3 (directly on UART port)
also Gsreamer doesn't want to load the pipe, but it opens fine in commend Prompt
gst-launch-1.0.exe -e -v udpsrc port=5000 ! application/x-rtp, payload=96 ! rtpjitterbuffer latency=10 ! rtph264depay ! avdec_h264 ! fpsdisplaysink