i dont get any LP when taking first place in tft ranked games

Is it a bug? I played all of my first 5 placement, finished 1st, 2nd, 6th, 8th, 5th. After my first win it preliminary placed me in Bronze something, might have been 4, 1LP, I then finished 2nd and lost LP. My placements placed be Bronze IV 1LP. Apparently, finished 1st and 2nd out of 5 = worst player, :P