1. Try to Join the instance
  2. It doesn't work, and I get sent back to my home world
This persists even after 3 re-uploads of the same content.
In the VRChat log I see these logs:
Asset bundle request failed: result=4 code=200 error=Data Processing Error, see Download Handler error dhError=CRC Mismatch. Provided 4468716b, calculated 9a456ad9 from data. Will not load AssetBundle 'https://api.vrchat.cloud/api/1/file/file_<uuidv4>/93/variant/security?v=1780757443'
[Unknown] Failed creating world instance wrld_e1548481-417c-4b2e-b2be-7e49ce669549:57046~hidden(usr_4863efc2-573e-4495-9bb3-7d3fec29e705)~region(eu)~nonce(ada3bcd3-878f-48aa-ad9e-5a044a62fb0f): Bad response data.
Error Downloading or Instantiating Custom Scene - Club NeoLuma - Unstable Dev - 12 - Error loading asset bundle from ****: Data Processing Error, see Download Handler error
Edit:
Updating the World doesn't fix it, contrary to other bugreports (ref. https://feedback.vrchat.com/bug-reports/p/world-corrupted-after-vrchats-outage )
After I deleted some unity temporary folders (I think it was Library) uploads were un-bricked.
I still think that uploads shouldn't break consistently like described.