There is a possibility that there is a tiny metal chip from manufacturing that may be preventing the valve from closing. I’ve seen it before. Disassemble the adjuster ( circled in red in photo) but first measure the distance between the lock nut and underside of the head of adjuster screw or count turns or anything to reassemble to same setting.
Once dissassembled look into valve to see if there’s any crud. Remove with cotton swab or shop vac with a straw.
Look at valve seat and valve to see of there’s any damage. If damaged, depending on your skills or available equipment you may be able to repair it, if not you would need to order a new one.
Second photo shows a chip found in one.
Good luck sir.
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