Keyshawn Johnson Unloads His Bieber-Adjacent Mansion -- He's Kourtney Kardashian's Problem Now

EXCLUSIVE

Keyshawn Johnson has just shed 140 unwanted pounds ... because he's officially moving far away from Justin Bieber ... and sadly for her, Kourtney Kardashian is gaining 140 lbs.

Our real estate spies tell us ... Kourtney paid just over $8.4 million for Keyshawn's 6-bedroom 9-bathroom 11,746 sq. ft. home in The Oaks -- located just blocks away from Bieber's Calabasas compound. The deal will close in less than 2 weeks.

We're told Keyshawn's move has nothing to do with Bieber, but we know Keyshawn despises the kid and has had numerous run ins, the latest of which was a nuclear fight with Justin's bodyguards outside the singer's house the night of the egging incident .

As for Kourtney ... she's upgrading -- she's listed her house for $3.5 mil.