Question Only opaque object post-processing and multiple passes in SRP

In my scriptable render pipeline, I added a post-processing after rendering opaque objects, and then continued rendering skybox and transparent objects.

But when I add multiple passes to the transparent object (for shell-based fur rendering), I found that rendering results were problematic on the phone when the number of passes exceeded 2. Or there is no problem but GMEM_LoadDepth will be triggered (this will cause serious bandwidth issues even though I have set LoadAction to DontCare)

I tried many ways, but I couldn't solve the problem. Is this a Unity Bug, or is there something wrong with my part of the design?

the codes are as follows:

Code (CSharp):

1.         // Opaque
2.         SortingSettings sortingSettings = new SortingSettings(camera)
3.         {
4.             criteria = SortingCriteria.CommonOpaque
5.         };
6.         DrawingSettings drawingSettings = new DrawingSettings(BPipline.bshaderTagIds[0], sortingSettings)
7.         {
8.             enableDynamicBatching = useDynamicBatching,
9.             enableInstancing = useGPUInstancing,
10.             perObjectData =
11.             PerObjectData.ReflectionProbes |
12.             PerObjectData.Lightmaps |
13.             PerObjectData.ShadowMask |
14.             PerObjectData.OcclusionProbe |
15.             PerObjectData.LightProbe |
16.             PerObjectData.LightProbeProxyVolume |
17.             PerObjectData.OcclusionProbeProxyVolume |
18.             lightsPerObjectFlags
19.         };
20.         // Set Multi-Pass
21.         for (int i = 1; i < BPipline.bshaderTagIds.Length; ++i)
22.         {
23.             drawingSettings.SetShaderPassName(i, BPipline.bshaderTagIds[i]);
24.         }
25.         FilteringSettings filteringSettings = new FilteringSettings(RenderQueueRange.opaque);
26.         context.DrawRenderers(cullingResults, ref drawingSettings, ref filteringSettings);
27.  
28.         // PostProcess Before Transparent
29.         if (postprocessProfiler.isActive && postprocessSettings.ssao.enable)
30.         {
31.             postprocessProfiler.Render_BeforeTransparent(colorBufferId, renderTargetBinding);
32.         }
33.  
34.         context.DrawSkybox(camera);
35.  
36.         // Transparent
37.         sortingSettings.criteria = SortingCriteria.CommonTransparent;
38.         drawingSettings.sortingSettings = sortingSettings;
39.         filteringSettings.renderQueueRange = RenderQueueRange.transparent;
40.         context.DrawRenderers(cullingResults, ref drawingSettings, ref filteringSettings);

Code (CSharp):

1.     public void Render_BeforeTransparent(int colorBuffer,    RenderTargetBinding renderTargetBinding)
2.     {
3.         PostProcessSettings.SSAO_Settings ssao = postprocessSettings.ssao;
4.         int width = camera.pixelWidth;
5.         int height = camera.pixelHeight;
6.  
7.         int sourceTarget = colorBuffer;
8.         int destTarget = destinationId;
9.         commandBuffer_beforeTransparent.GetTemporaryRT(destinationId, width, height, 0, postprocessSettings.filterMode, postprocessSettings.renderTextureFormat);
10.  
11.         Vector2Int rtSize = new Vector2Int(width >> ssao.downSample, height >> ssao.downSample);
12.         commandBuffer_beforeTransparent.GetTemporaryRT(ssaoRt0, rtSize.x, rtSize.y, 0, FilterMode.Bilinear, GraphicsFormat.R8_UNorm);
13.         commandBuffer_beforeTransparent.GetTemporaryRT(ssaoRt1, rtSize.x, rtSize.y, 0, FilterMode.Bilinear, GraphicsFormat.R8_UNorm);
14.  
15.         commandBuffer_beforeTransparent.SetGlobalVector("_AO_Scales", new Vector4(ssao.aoStrength, ssao.sampleScale / rtSize.x, ssao.sampleScale / rtSize.y, 0.5f));
16.         Draw_BeforeTransparent(destTarget, ssaoRt0, Pass.SSAO);
17.  
18.         for (int i = 0; i < 3; i++)
19.         {
20.             commandBuffer_beforeTransparent.SetGlobalVector("_BlurOffset", new Vector4(ssao.blurScale / rtSize.x, 0.0f));
21.             Draw_BeforeTransparent(ssaoRt0, ssaoRt1, Pass.GaussianBlur);
22.  
23.             commandBuffer_beforeTransparent.SetGlobalVector("_BlurOffset", new Vector4(0.0f, ssao.blurScale / rtSize.y));
24.             Draw_BeforeTransparent(ssaoRt1, ssaoRt0, Pass.GaussianBlur);
25.         }
26.  
27.         commandBuffer_beforeTransparent.SetGlobalTexture("_PostProcessBlend", ssaoRt0);
28.         Draw_BeforeTransparent(sourceTarget, destTarget, Pass.BlendMulR);
29.  
30.         // Because I am using MRT, I need to reset back to MRT after the post-processing (LoadAction is DontCare)
31.         commandBuffer_beforeTransparent.SetGlobalTexture(sourceId, destTarget);
32.         commandBuffer_beforeTransparent.SetRenderTarget(renderTargetBinding);
33.         commandBuffer_beforeTransparent.DrawProcedural(Matrix4x4.identity, postprocessSettings.Material, (int)Pass.Copy, MeshTopology.Triangles, 3);
34.  
35.         commandBuffer_beforeTransparent.ReleaseTemporaryRT(ssaoRt0);
36.         commandBuffer_beforeTransparent.ReleaseTemporaryRT(ssaoRt1);
37.         commandBuffer_beforeTransparent.ReleaseTemporaryRT(destinationId);
38.  
39.         Execute_BeforeTransparent();
40.     }