MHT to PDF conversion fails with "An item with the same key has already been added. Key: font-size"

Aspose.PDF Cloud Product Family
1

Calling PdfApi.GetMhtInStorageToPdf() via the .NET SDK. For a broad set of inputs, it intermittently fails with an “internalError” code.

Sample:

{
    "RequestId": "06952c9f715605a885bb95da55d5e33d",
    "Error": {
        "Code": "internalError",
        "Message": "An item with the same key has already been added. Key: font-size",
        "Description": "Operation Failed. Internal error.",
        "DateTime": "2026-09-29T01:28:44.3682834Z",
        "InnerError": null
    }
}

Can supply example inputs if required.