UE5 Cloth Simulation BUG, Vertex do not move

Hey Guys, I’ve been playing the cloth system for a while. I made a flag and paint the weight, adjusting the parameters, Everything went right. But after I playing these parameters for a while , There are some Vertices Stick around and Dont move with the simulation, and after I reverted all the changes on parameters and even repainted the weight, It still did not move. Is this the cloth bug? Can someone give me some advice :smiling_face_with_tear: