Terrain: 500 Internal server errors all the time

Many / All requests result in 500 “Internal server error” in the last few hours at least, for example:
GET https://assets.ion.cesium.com/1635234/14/17447/12456.terrain?extensions=octvertexnormals-metadata&v=1.193.0

another example with Cesium World Terrain:

GET https://assets.ion.cesium.com/asset_depot/1/CesiumWorldTerrain/v1.2/13/8588/6221.terrain?extensions=octvertexnormals-metadata&v=1.2.0

Status: 500 Internal Server Error

Please see AWS Outage affecting Cesium ion