We've seen this for various PRs (#488, #496, #507, #512, #514)
The last successful run was using Apptainer 1.2.5 (https://github.com/EESSI/software-layer/actions/runs/8284497353).
As a short-time workaround we stick to Apptainer < 1.3.0 (#516).
We should revert that change either when a newer Apptainer works again or when we have found another solution to the issue (e.g., running apptainer with additional arguments such as --underlay)