In ECM-13.0, the bi-directional optical flow (BDOF) tool is only applied to refine the prediction samples of the inter CUs with “true” bi-prediction, i.e., two reference pictures are from two different direction with regard to the current picture. In this contribution, it is proposed to enable the BDOF for the bi-predictive CUs with both reference pictures from the same direction. Simulation results show that the proposed change provides 0.12% BD-rate savings for the LDB configuration with minor enc/dec runtime impacts.