Custom quantized-mesh terrain not rendered on higher levels

We upgraded from Cesium 1.56.1 to 1.58 and our terrain is disappearing on higher zoom levels.
We use a custom terrain server with quantized-mesh-1.0 to generate world wide terrain data up to 10cm

In some rare cases, I do get terrain data, and from there on its working fine. Deleting the browser cache and the problem re-appears.

It seems that the missing tiles are never requested

Sandcastle example:
Our terrain server is not public, but the test was very basic:

var viewer = new Cesium.Viewer('cesiumContainer');
viewer.terrainProvider = new Cesium.CesiumTerrainProvider({url:"http://localhost:8281/terrain/"});

The generated layer.json can be found here:
[https://pastebin.com/d4m9KHF5](url)

To see the sandcastle example, I made a small video

[https://youtu.be/F4fsKBxFY-4](url)

Browser:
Chrome 75.0.3770.100

Start with the CesiumTerrainProvider setup shown in the issue and reproduce the missing higher-level requests against the local quantized-mesh server. Compare behavior with the supplied layer.json and Sandcastle video, then verify that higher zoom terrain tiles are requested and rendered consistently after the fix.

Written by the indexing model from the issue text.