vertex displacement shader and ssao

hi

we are using a bunch of vertex shaders in our game that applies sinus curves to vert positions so that all kinds of foliage can sway in the wind.

when i turn on the build in screen space ambient occlusion too the "darkend" areas remain static where the grass originally was before it started displacing.

what do i need to change on the shader (or ssao image effect) to make these 2 effects play along together nicely ?

... the ssao grabs what exactly from the frame buffer to perform its magic ? the normals ? also the depth right ? could it be that my displacement/wobble/shader doesnt update one of them in the framebuffer and needs some extra code to do it:

     Shader "ese_wobble_masked_pixellit"
 {
     Properties 
     {
 _MainTex("_MainTex", 2D) = "white" {}
 _frequency("_frequency", Float) = 1
 _speed("_speed", Float) = 1
 _scale_x("_scale_x", Float) = 0.1
 _scale_y("_scale_y", Float) = 0.1
 _scale_z("_scale_z", Float) = 1
 _alpha_threshold("_alpha_threshold", Range(0.01,0.99) ) = 0.5
 
     }
     
     SubShader 
     {
         Tags
         {
 "Queue"="Geometry"
 "IgnoreProjector"="True"
 "RenderType"="TransparentCutout"
 
         }
 
         
 Cull Off
 ZWrite On
 ZTest LEqual
 ColorMask RGBA
 Fog{
 }
 
 
         CGPROGRAM
 #pragma surface surf Lambert  addshadow vertex:vert nolightmap noforwardadd
 #pragma target 2.0
 
 
 sampler2D _MainTex;
 float _frequency;
 float _speed;
 float _scale_x;
 float _scale_y;
 float _scale_z;
 float _alpha_threshold;
 
             
             struct Input {
                 float2 uv_MainTex;
                 float4 color : COLOR;
 
             };
 
             void vert (inout appdata_full v, out Input o) {
                 float4 Splat2=v.texcoord1.y;
                 float4 Splat1=v.texcoord1.x;
                 float4 Multiply4=_Time * _speed.xxxx;
                 float4 Add2=v.vertex + Multiply4;
                 float4 Splat3=Add2.z;
                 float4 Multiply3=Splat3 * _frequency.xxxx;
                 float4 Add4=Splat1 + Multiply3;
                 float4 Sin1=sin(Add4);
                 float4 Multiply0=_scale_x.xxxx * Sin1;
                 float4 Multiply2=_scale_y.xxxx * Sin1;
                 float4 Multiply5=_scale_z.xxxx * Sin1;
                 float4 Assemble0=float4(Multiply0.x, Multiply2.y, Multiply5.z, 0);
                 float4 Multiply7=Splat2 * Assemble0;
                 float4 Add1=Multiply7 + v.vertex;
                 float4 VertexOutputMaster0_1_NoInput = float4(0,0,0,0);
                 float4 VertexOutputMaster0_2_NoInput = float4(0,0,0,0);
                 float4 VertexOutputMaster0_3_NoInput = float4(0,0,0,0);
                 v.vertex = Add1;
             }
             
 
             void surf (Input IN, inout SurfaceOutput o) {
                 o.Normal = float3(0.0,0.0,1.0);
                 o.Alpha = 1.0;
                 o.Albedo = 0.0;
                 o.Emission = 0.0;
                 o.Gloss = 0.0;
                 o.Specular = 0.0;
                 
                 float4 Tex2D0=tex2D(_MainTex,(IN.uv_MainTex.xyxy).xy);
                 float4 Multiply0=Tex2D0 * IN.color;
                 float4 Subtract0=Tex2D0.aaaa - _alpha_threshold.xxxx;
                 clip( Subtract0 );
                 o.Albedo = Multiply0;
             }
         ENDCG
     }
     Fallback "Transparent/Cutout/VertexLit"
 }