Has anyone noticed more matches where neither team tries to win?

after coming back from a break of about 3 months i started playing in june again and for whatever reason the matches i've been playing are constant back and forths where either 1 member of the team will leave and it will be 4v5 so the 5 man team doesnt want to win or there will be someone talking in all chat to the other team helping them out instead of trying to win. has anyone else noticed this trend or is it just me?

literally the last 9 games i've played have all ended post 45 minutes in when in reality they should have ended at the 15 minute mark - 20 minute mark easily. we're talking about matches where all of the enemy teams turrets are gone and all 3 inhibitors are open, but no one pushes for the inhibitors to close out the game. is this some sort of new trolling tactic or way to increase a particular stat like mastery? because it's highly unusual behavior and really annoying.