FW failsafe: no global position = crash

I’m trying to determine the cause of a recent crash and how to prevent it in the future. I was unsure of the direct cause of the crash at first, but replaying the tlog in QGC, it seems apparent that the global position failsafe caused a switch to Land mode, which then sent the plane into an unrecoverable death spiral. Why would there be no global position all of a sudden? Why would Land mode cause it to lose control? @dagar

Here is the log

PX4 Firmware issue opened. https://github.com/PX4/Firmware/issues/7609