Mark Munoz -- a former UFC fighter who beat Demian Maia in 2011 -- has been placed on administrative leave from his high school wrestling coach job ... after he let quarrelling students box each other, TMZ Sports has learned.
Munoz accepted a job to be the H.S. wrestling coach at Fairmont Private Schools in Anaheim, Calif. back in Sept. 2020 -- but we're told things at the gig went awry just recently.
According to sources close to Munoz, two students got into an argument on the playground .