Drone Processing problem

I am processing a drone project where I have GCP’s along the Drone’s imagery.

I have aligned the images and assigned GCP’s to photos then run the Align Images again.

Settings - Use Camera Priors… NO

Prior Pose set to Unknown

Brown4 with Tangential2

I am getting a residual line on a GCP that is causing the project to curve down in elevation.

When I look at the altitude for the GCP (Actual Position) in question is is almost 10m lower than then measured GCP.

I have not had it where the GCP coordinate is not being held.

Having GCP’s has always made any “banana” effect go away.

Any suggestions?