Why the GCP can see double, and join with a green line, but in a different area?
Thank you for your question.
The line connects the initial position to the computed position.
There can be many causes for this. Make sure the coordinates of your GCPs are not swapped between different points and that you marked the correct GCP in the images, belonging to the selected GCPs in your list.
If the error still appears, please share the quality report with us.