Hey!
I have big problems controlling my ROV.
We were down on a steel wreck 85 meters deep (280 feet) and suddenly it wants to spin around. I also get a message saying “Warning: EKF2 IMUO ground mag anomaly, yaw re-aligned”.
What tips do you have, so here you can not have it 
//Niklas Sweden
It sounds like the magnetics from the wreck hull is giving you deviation on the compass.
I have encountered that myself on several iron wrecks.
Only thing to do if you want a correct heading info is to go further away from the wreck magnetics.
And do not use auto heading when close to the wreck.