The limits are there. -500€/MWh and 4000€/MWh. It did hit the lower limit for 10 hours in the row from 14:00 till midnight. Before 14:00 they were not the last bidder, so prices are higher there. Price on the market for everyone is set by the last bidder who fits in the predicted consumption pool.
They have price limits, but I think GP means volume alert limits. Someone unexpectedly bids a third of the Finnish production capacity, you call them and ask if they are sure.
