I did some investigation in the linked post, and it strongly looks like this is the same issue here. Specifically: It is not that this data is not loaded. It is only occluded by what appears to be a huge wall…
My guess until now (and it’s a pretty wild guess, but not totally unreasonable) is that this is an instance of Wrong tiles selected for refinement in certain areas · Issue #12683 · CesiumGS/cesium · GitHub : It might be that it is selecting and rendering a level of detail that is just very, very wrong. It could be a tile that should only be rendered for a zoom level that shows ~“nearly the whole globe”.
In the linked post, you said
It’s unclear to me whether this is a data issue (Google) or a renderer issue (Cesium).
Iff it is an instance of that issue (which still has to be confirmed!), then it’s apparently a CesiumJS issue - at least, there recently was a post with a direct comparison of CesiumJS and the ThreeJS renderer at Rendering issue with cesium sandcastle and js - #4 by Alok_Maurya , where that issue seemed to only appear in CesiumJS.