Azure Attestation TPM sample reaches round 1 InvalidDataField — request Severity C support case

We purchased Azure Standard support to open a development Severity C technical case. The portal routes the request to Microsoft Q&A rather than allowing case creation. Please advise how to submit this Azure Attestation technical case securely if a private support case is required.

We are evaluating Azure Attestation for a development-only Windows 11 TPM 2.0 device-assurance path. No production workload, customer data, registered devices, or offline permits are involved.

On a physical Windows 11 TPM 2.0 device, AIK enrollment succeeds and Azure accepts protocol round 0. The evidence-bearing round 1 consistently returns HTTP 400 with the bounded server code invalid_data_field, and no attestation report is produced.

The final reproduction preserves the current Microsoft TPM sample's native construction: Microsoft Platform Crypto Provider, machine AIK, provider-default RSA-2048 request key, official ATT_TPM wrappers, and no other_keys. It uses Microsoft.Attestation.Client 1.1.133870390-preview, REST API 2020-10-01, and the Microsoft sample source baseline at commit 84a502dcbedb674b505262f3eee022fd88ebc3ef. A strict valid-AIK policy remains enabled.

Earlier managed and provider-default diagnostics produced the same round-1 result. The native parity result therefore makes our managed ABI and hardened request-key template unlikely leading causes on this device. Every bounded run cleaned up successfully; the final exact-prefix AIK count was zero. We retained no raw TPM evidence, token, key material, certificate, identifier, or response message.

Please confirm whether this package/API/sample combination is currently supported for TPM attestation; whether InvalidDataField at round 1 reflects evidence parsing or validation before policy evaluation; the relevant evidence field or compatibility condition; and the current supported client/sample/API combination. If raw evidence or identifiers are essential, please specify the minimum fields and an approved secure upload method before we collect them.