Jake Paul purposely ran away from his fight against Hasim Rahman Jr. ... so says the former boxing champ's son, who claims he easily could have made weight for their August 6 bout -- but the YouTube superstar got scared.
HRJ faced the music hours after Paul's Most Valuable Promotions announced the bout at Madison Square Garden was scrapped ... and he claims it's a sketchy situation.
Rahman claims he could've easily made weight for the fight ... but the Problem Child simply didn't want to risk losing.