What version of CesiumJS are you using? Are you able to reproduce this in Sandcastle? See: How to share custom Sandcastle examples
One difference between Cesium OSM Buildings and those other 3D Tilesets is that the tiles are Draco compressed. Decompression in CesiumJS uses WebAssembly. So it’s possible your browser/environment doesn’t support WASM for some reason?
Can you try running this (https://d2jta7o2zej4pf.cloudfront.net/) ? Does it say that your browser supports WASM?
(✓ WebAssembly is supported in your browser)