I was building in a "clean chroot" not chrooting.(guess I was chrooting but differently to how I chrooted before)
https://wiki.archlinux.org/title/DeveloperWiki:Building_in_a_clean_chroot
As to why, well the developer suggested it,
https://aur.archlinux.org/packages/auracle-git
Your second post mentions one common use as " Building packages in a clean chroot. "
Building in a clean chroot and then installing solved the glitch so I am happy. 😋