The owner and group fields are empty.

if: docker exec -ti puptest /bin/sh

Logical, because the container does not know the names of owner:group 1000:1000 inside the container.
The simples of fixes is to no longer show this info.
Just show the permissions info and I'm happy.
I really like the keep it simple approach of pupcloud.
Just kill off features that do not work and only add features that dd to the functionality of pupcloud! NO need to make the code bloated (and slower) with exceptions and workarounds.
Maybe make this a discussion, not an issue?