shader gpu animation problem in unity, how to dynamically change the animation every time from the first frame play

About unity shader, gpu animation

/*
Created by jiadong chen
https://jiadong-chen.medium.com/
*/

Shader "chenjd/BuiltIn/AnimMapShader"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        _AnimTex ("Texture", 2D) = "white" {}
        _AnimTime ("AnimTime", float) = 1
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 100
        
        Pass
        {
            CGPROGRAM
            #pragma target 3.5
            #pragma vertex vert
            #pragma fragment frag
            // make fog work
            #pragma multi_compile_instancing
            
            #include "UnityCG.cginc"
            
            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
                uint vid : SV_VERTEXID;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };
            
            struct v2f
            {
                float2 uv : TEXCOORD0;
                UNITY_FOG_COORDS(1)
                float4 vertex : SV_POSITION;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };
            
            CBUFFER_START(UnityPerMaterial)
                sampler2D _MainTex;
                sampler2D _AnimTex;
                
                UNITY_INSTANCING_BUFFER_START(Props)
                UNITY_DEFINE_INSTANCED_PROP(float4, _AnimTex_TexelSize)
                UNITY_DEFINE_INSTANCED_PROP(float4, _MainTex_ST)
                UNITY_DEFINE_INSTANCED_PROP(float, _AnimTime)
                UNITY_INSTANCING_BUFFER_END(Props)
            CBUFFER_END
            
            v2f vert (appdata v)
            {
                v2f o;                
                UNITY_SETUP_INSTANCE_ID(v);
                UNITY_TRANSFER_INSTANCE_ID(v, o);
                float4 uv_anim = float4((v.vid + 0.5) * UNITY_ACCESS_INSTANCED_PROP(Props, _AnimTex_TexelSize).x, _Time.y / UNITY_ACCESS_INSTANCED_PROP(Props, _AnimTime),0.0,0.0);
                v.vertex = float4(tex2Dlod(_AnimTex, uv_anim).xyz,1.0);
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = v.uv * UNITY_ACCESS_INSTANCED_PROP(Props, _MainTex_ST).xy + UNITY_ACCESS_INSTANCED_PROP(Props, _MainTex_ST).zw;
                return o;
            }
            
            fixed4 frag (v2f i) : SV_Target
            {
                UNITY_SETUP_INSTANCE_ID(i);
                fixed4 col = tex2D(_MainTex, i.uv);
                return col;
            }
            ENDCG
        }
    }
}

If I want to change the animation dynamically.
float4 uv_anim = float4((v.v.id + 0.5) * UNITY_ACCESS_INSTANCED_PROP(Props, _AnimTex_TexelSize).x, y/UNITY_ACCESS_INSTANCED_PROP(Props, _AnimTime),0.0,0.0);
here _Time.y/UNITY_ACCESS_INSTANCED_PROP(Props, _AnimTime),0.0,0.0); It should be the progress of the animation. But this time is always going on. So how can the animation start at frame 0 every time? I was debugging in the game scene and found that sometimes the animation didn't play from the beginning.