Apptainer v1.1.0 is out. Given the new features possibly new USE flags should be added (after exploring things), e.g., perhaps a squashfs flag, etc. Reproducible: Always
URL for Apptainer release: https://github.com/apptainer/apptainer/releases/tag/v1.1.0
apptainer-1.1.0 came out 2022-09-27 15:30 UTC, you opened this ticket on 2022-09-28 14:13 UTC. Please see https://wiki.gentoo.org/wiki/Zero-day_bump_requests .