I recently saw this and thought I'd reach out. Sorry you're dealing with this issue - I know how frustrating stuff like this can be
As Chad mentioned, please share your related log and parameters files. Curious, are you using Flight Core with a VOXL board or do you have the all in one VOXL Flight board?
For clarity, I assume when you use our parameters file: https://gitlab.com/voxl-public/flight-core-px4/px4-parameters/-/tree/master/platforms/v1.11, https://gitlab.com/voxl-public/flight-core-px4/px4-parameters/-/tree/master/helpers
and Use the indoor and outdoor helpers, does the ekf2_aid_mask correctly set?
For reference, this is the EKF2_AID_MASK parameter listing:
The error you list "Estimator source 8 not supported." seems odd. Are you not providing VIO nor optic flow input?
Also from my understanding, if you would like to use GPS yaw fusion, GPS needs to be used or enabled in the bit, since it's integrating GPS yaw.
So, I'm thinking you would want value 165 --> 1 0 1 0 0 1 0 1 --> Mask: 0 (GPS), 2(imu bias), 5 (drag fusion), 7 (GPS yaw).
I've never used the drag fusion bit, so unsure how that's supposed to behave. Maybe other parameters need to be tuned and updated? https://docs.px4.io/master/en/advanced_config/tuning_the_ecl_ekf.html#multicopter-wind-estimation-using-drag-specific-forces