What are the downloaded files permission with the UMASK for you?
The UMASK parameter is not doing anything for me.
The default UMASK 022 is applied no matter what UMASK I specify.
I logged into the Docker's console (click on the docker then select console), I typed umask and it returned 0022.
If I check the files permissions, they are at -rw-r--r-- (UMASK 022) while it should be -rw-rw-rw- if UMASK is really 000.