Test service URL: Services Directory - Test_Elevation_Tile_Map(ImageServer)
Test service description: The original data is in TIF format with a 3857 coordinate system, using the ArcGIS Online/Bing Maps/Google Maps tiling scheme, with LOD levels 0-16.
ArcGIS Loading Verification: Can be loaded and displayed normally in ArcGIS.As shown in the figure below：
Cesium Test example: Cesium Sandcastle
My issue is the same as described in this link. By tracing the source code, it enters an infinite loop at this point.And I have also submitted this issue on GitHub.
Any response would be greatly appreciated. 
Lauxb