can somebody pls explain to me why this is a draw ?

Partner did his move - then System says it is draw:

The final positons accured 3 times. Following the fide rules both players have the chance to claim a draw in that case.

3 fold repetition.

Lichess has a wrong implementation of threefold, so the player couldn't request a threefold in the correct way, by writing his move on the scoresheet and stop the clock, to go to the arbiter to request a threefold with this reputation. You have to move at first, you can't claim threefold in the correct order. One or two times my opponent was to fast, that I couldn't claim the draw. Even another wrong implementation was made, the system shows you that this position was three times on the board, normally you don't know before requesting threefold. After a wrong request your opponent gets time. If you are wrong for the second time, you lose the game.

Lol @ich_bin_du