HDRP - Shader is SRP batcher compatible, but separate pass isn't

Is there a way to debug what’s causing this? I’m using Frame Debugger to track down draw calls, and it seems one of the shader passes do not SRP batch correctly:
6190950--678870--upload_2020-8-11_12-11-0.png

However, shader inspector shows that it is compatible:
6190950--678873--upload_2020-8-11_12-17-36.png

Here’s how CBUFFER of Depth Only pass looks like:

            CBUFFER_START( UnityPerMaterial )
            float4 _ST_WindTurbulences;
            float4 _ST_WindLeaf1Tumble;
            float4 _ST_WindAnimation;
            float4 _ST_WindFrondRipple;
            int _Cull;
            float4 _ST_WindBranchWhip;
            float4 _ST_WindLeaf1Twitch;
            float4 _ST_WindBranch;
            float4 _ST_WindLeaf2Tumble;
            float4 _ST_WindBranchAdherences;
            float4 _ST_WindLeaf2Ripple;
            float4 _ST_WindLeaf2Twitch;
            float4 _ST_WindLeaf1Ripple;
            float4 _ST_WindBranchTwitch;
            float4 _ST_WindGlobal;
            int _WindQuality;
            int _GlobalTimerId;
            float4 _Color;
            float4 _ST_WindVector;
            float4 _ST_WindBranchAnchor;
            float _Cutoff;
            float _Metallic;
            float _Smoothness;
            float4 _EmissionColor;
            float _RenderQueueType;
            float _StencilRef;
            float _StencilWriteMask;
            float _StencilRefDepth;
            float _StencilWriteMaskDepth;
            float _StencilRefMV;
            float _StencilWriteMaskMV;
            float _StencilRefDistortionVec;
            float _StencilWriteMaskDistortionVec;
            float _StencilWriteMaskGBuffer;
            float _StencilRefGBuffer;
            float _ZTestGBuffer;
            float _RequireSplitLighting;
            float _ReceivesSSR;
            float _SurfaceType;
            float _BlendMode;
            float _SrcBlend;
            float _DstBlend;
            float _AlphaSrcBlend;
            float _AlphaDstBlend;
            float _ZWrite;
            float _CullMode;
            float _TransparentSortPriority;
            float _CullModeForward;
            float _TransparentCullMode;
            float _ZTestDepthEqualForOpaque;
            float _ZTestTransparent;
            float _TransparentBackfaceEnable;
            float _AlphaCutoffEnable;
            float _AlphaCutoff;
            float _UseShadowThreshold;
            float _DoubleSidedEnable;
            float _DoubleSidedNormalMode;
            float4 _DoubleSidedConstants;
            CBUFFER_END

Is there a way to debug what’s causing this alike when shader isn’t compatble?
Or is there any other limitation that can cause SRP batch to break?

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