"MAG INTERF"
"Magnetic Field Interference. Fly with caution"

I get this whenever the Mavic is turned on while the arms are folded in, but twice today I also got this while the arms were unfolded, and my last flight was unstable as a result.

Have you experienced this?

I read one person post that this is a result of lack of magnetic shielding on some Mavic's rear compass resulting in it getting interference from the motors, and that the latest January firmware update fixes this Hardware issue with a Software patch that essentially tells it to instead use the front compass, but that if this is reported to DJI they would replace your drone due to faulty shielding.

Is this true? Thoughts?

UPDATE: I found the cause: I need to have the legs of the Mavic extended, otherwise the motors themselves produce enough magnetic interference to cause this issue.