Issue with keys in POST /assets API - Asset stuck in "retrieving files" state

Cesium ion
1

I’ve been using the POST /assets API for a while now to upload terrain data via S3 using the keys parameter. It was working perfectly fine until recently (past 1-2 days), and now I’m consistently running into an issue where the asset gets stuck in the “retrieving files” state when using the keys array.

Here’s the payload I’m using (sanitized creds of course):

{
    "name": "Testing",
    "description": "Testing",
    "type": "TERRAIN",
    "options": {
        "sourceType": "RASTER_TERRAIN",
        "baseTerrainId": 1
    },
    "from": {
        "type": "S3",
        "bucket": "map-assets",
        "credentials": {
            "accessKey": "accessKey",
            "secretAccessKey": "secretKey"
        },
        "keys": ["66a00ab8-811c-4c35-8a0f-ee4b9ee8273b/dem.tif"]
    }
}

When I switch to using prefixes instead of keys, the asset uploads and processes just fine — so this definitely feels like a regression or change in behavior on Cesium’s end.

Was there any recent update to how the keys parameter is handled?
Would appreciate some insight here.

Thanks.