Hi, It turns out this was due to the fact that I had ironclad git cloned on my computer, which was accidentally visible via :tree in the ASDF configuration. ASDF detected that a different ironclad was used and tried to compile-file to the gnu/store. I thought it was guix-related since it did occur with both --pure and --container, but I was running it with the default cwd share on.
Using --container --no-cwd is the solution to this problem.