((a)) Where there is affirmative evidence to the contrary, or evidence to establish that an intercurrent injury or disease which is a recognized cause of any of the diseases or disabilities within the purview of section 1112, 1116, 1117, 1118, or 1120 of this title, has been suffered between the date of separation from service and the onset of any such diseases or disabilities, or the disability is due to the veteran’s own willful misconduct, service-connection pursuant to section 1112, 1116, 1118, or 1120 of this title, or payments of compensation pursuant to , will not be in order.

((b)) Nothing in section 1112, 1116, 1117, 1118, or 1120 of this title, subsection (a) of this section, or ( note) shall be construed to prevent the granting of service-connection for any disease or disorder otherwise shown by sound judgment to have been incurred in or aggravated by active military, naval, air, or space service.