ProductionOrderDetail OperationDescription After 25R2 Update

I have a program that PUTs Production Orders via REST API. It worked until our recent upgrade from 24R2 to 25R2. I was using endpoint version 23.200.001 but it happens with 25.100.001 also.

I PUT to ~entity/MANUFACTURING/25.100.001/ProductionOrderDetail?$expand=Operations&$select=Operations/OperationDescription:

{
    "OrderType": {
        "value": "RG"
    },
    "ProductionNbr": {
        "value": "TESTORD"
    },
    "Operations": [
        {
            "ControlPoint": {
                "value": true
            },
            "OperationNbr": {
                "value": "010"
            },
            "WorkCenter": {
                "value": "SAW"
            },
            "rowNumber": {
                "value": 1
            },
            "OperationDescription": {
                "value": "Cut 12\""
            }
        }
    ]
}

And it responds 200:

{
    "id": "ca50efb0-01c4-f011-843a-06b1b982e321",
    "rowNumber": 1,

    "Operations": [
        {
            "id": "0846d663-06c4-f011-843a-06b1b982e321",
            "rowNumber": 1,
            "note": {
                "value": ""
            },
            "ControlPoint": {
                "value": true
            },
            "Material": [],
            "OperationDescription": {
                "value": "Saw Cutting"
            },
            "OperationNbr": {
                "value": "010"
            },
            "OutsideProcess": {
                "value": false
            },
            "QueueTime": {
                "value": 960
            },
            "RunTime": {
                "value": 60
            },
            "RunUnits": {
                "value": 0.000000
            },
            "SetupTime": {
                "value": 0
            },
            "WorkCenter": {
                "value": "SAW"
            },
            "custom": {},
            "_links": {
                "files:put": "/entity/MANUFACTURING/25.100.001/files/PX.Objects.AM.ProdDetail/ProdOperRecords/0846d663-06c4-f011-843a-06b1b982e321/{filename}"
            }
        },

    ],
    "OrderType": {
        "value": "RG"
    },
    "ProductionNbr": {
        "value": "189995-001"
    },

    "custom": {},
    "_links": {
        "self": "/entity/MANUFACTURING/25.100.001/ProductionOrderDetail/ca50efb0-01c4-f011-843a-06b1b982e321",
        "files:put": "/entity/MANUFACTURING/25.100.001/files/PX.Objects.AM.ProdDetail/ProdItemRecords/ca50efb0-01c4-f011-843a-06b1b982e321/{filename}"
    }
}

I’ve tried moving the JSON around, tried when adding new lines and editing existing, with and without the id populated. I cannot replicate this problem via UI, it only occurs in the API.

Any idea how I can repair this? Is this a known issue?

Thanks for reading.