I need to correct a small problem with a metal gate post. When the gate is opened to its full opening, the leverage of the gate pulling against the gate post causes the post to spin inside the post hole and then the gate becomes misaligned with the attachment mechanism (on the right of the gate). Other than this, the post itself is very secure and stable. In the attached image, the post on the left of the gate spins inside of its post hole when the gate is opened fully. Additional image is provided to give you more detail on the post installation.
I'm trying to find a remedy to stop the post from spinning, but that does not require removing the fence post. Why? — I don't believe there is adequate space around the post to dig it out and reseat it (due to the large amount of concrete surrounding the post).
Please let me know what ideas you have.