Questions regarding lateral acceleration gradient derivation

[mamariomiamo]

Hi, I am not sure if the following gradient is derived accurately? It seems to suppose to have 3 terms but there are only 2 terms. The 2 terms are also seem to be slightly off. The corresponding equations in paper is (20) and (21b) https://github.com/ZJU-FAST-Lab/Dftpav/blob/main/src/Plan/traj_planner/src/traj_optimizer.cpp#L671-L672