Here is the “offending” section:”
(iv) A record that identifies a person who has been adjudicated mentally defective or committed to a mental institution (as determined in regulations implementing section 922(g)(4) of title 18, United States Code, as in effect on the date of the enactment of this Act) and whose record is not protected from disclosure to the Attorney General under any provision of State or Federal law.
A simple PTSD diagnosis isn't the same as being adjuacted mentally defective.