I set the APP_URL before the container was created. When I changed it, I deleted the container and all mapped folders so it each time it was completely clean…
I found this thread mentioning the same issue and based on that I was able to confirm that if you chmod the folder with the long random name here app_storage/app/public/<LongRandomName>/ to 755 then the logo shows properly.
In that thread @david said:
…I believe there is a PR that will make the logo appear within the admin panel, which should resolve that particular issue.
It seems this is a known issue then. Can you or David help point me to the PR so I can follow it?