Quick answer: Unity material using InstanceID property breaking SRP Batcher? InstanceID is per-instance; SRP Batcher requires per-material CBuffer - use ManualBatch flag or restructure.
Stylized water shader uses INSTANCE_ID. Frame Debugger: SRP Batcher off.
Remove InstanceID
If per-instance variation isn't critical, drop. Batcher reclaimed.
Or use GPU Instancing
InstanceID via DOTS_INSTANCING_ON; different batching path.
Audit batcher compatibility
Frame Debugger lists Reason for each non-batched material. InstanceID = one cause.
“SRP Batcher and InstanceID conflict. Choose one.”
If batching matters, audit shaders for InstanceID. Each is a candidate for refactor.