It shouldn’t be happening at all.
What this means is that QGC has not decoded a HEARTBEAT message from the autopilot for at least 3 seconds (the autopilot sends the message at 1Hz).
So this is an issue with communication between the autopilot and QGC. Things to check would be:
- Bandwidth test at 192.168.2.2:2770/network
- Tether conductors are well seated/tight in interface boards
- Interface board has adequate power supply
- Try switching cables for new ones
Do you have any issues with the video when this happens?
If you can record a telemetry log file where this happens, then send me the log file that might help to narrow the issue.