In current VVC, Intra Subblock Partitioning and Multiple Reference Line are disallowed for the non-Most Probable Modes. However, the on/off control flag of Intra Subblock Partitioning and the reference line index are still signalled for such intra prediction methods, which is unnecessary. To tackle this problem, this contribution proposes to signal the on/off control flag of Intra Subblock Partitioning and the reference line index only when Most Probable Mode is used. It is reported that the proposed method can obtain 0.01% luma BD-rate gain for the AI and RA configurations on top of VTM-5.0 without encoding and decoding run-time changes.