So something in one of the latest update to Brave has cause BJS to act extremally volatile. You can load a scene and it will be hit or miss on if it even propagates, then if you do any sort of intensive asset parsing it is very unpredictable on if it will actually resolve or not.
This was confirmed by one of my peers on a completely different project with no shared codebase.
If you are struggling right now with BJS stuff and are using Brave, switch browsers.
If you can confirm on your end or not that will help quite a bit. If it turns out that its not happening to you, Ill uninstall brave entirely and reinstall to see if that fixes it and request that my peer who is experience the same issues do the same.
Its seeming to be directly related to assetContainers and fileTools parsing blobs and animation parsing.