Ahah. Looking at your UAV file, I see that you are using DShot which you weren't in 16.09... I recently tracked down some problems to DShot and after looking at the code, I suggest that you don't use DShot, or if you absolutely must, you should use only the very fastest DShot=1200. The DShot code disables interrupts, then bit bangs the DShot bits out, then enables interrupts. That is uh, not the way a real time, interrupt driven system should, uh...
https://forum.librepilot.org/index.php?topic=4883.msg32723#msg32723Switch to something besides DShot, even if your ESCs don't work, just for a test to see if the warning goes away.
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Suggestions I wrote before finding that you were using DShot. You may find them useful if DShot isn't the issue:
Waiting for steady is associated with Basic/Complementary, so I suspect that there is a warning, but it is not actually a waiting for steady issue.
I suspect that checking the box just reinits the Atti and doesn't really do anything when using INS13.
What does the Primary Flight Display show on the Flight Data page? With vehicle stationary, does the PFC move around? Also, instead of checking the box, if you rotate the vehicle around in different directions, you may find that the warning goes away (to help diagnose).
In the past when I have had this issue (mainly 16.09), it has been sensor calibration. In particular, mag sensor.
I grepped in the code and found one match:
flight/modules/StateEstimation/stateestimation.c: AlarmsSet(SYSTEMALARMS_ALARM_ATTITUDE, SYSTEMALARMS_ALARM_WARNING);
which does say that one of the sensors did not send data.