Invalid configuration: root partition not found” with encrypted root, even when root is correctly mounted

Which ISO version are you using?

https://fastly.mirror.pkgbuild.com/iso/2026.01.01/archlinux-x86_64.iso

The installation log

ryzen 7 9700x
nvidia RTX4060
nvme

describe the problem

While installing Arch Linux using archinstall with an encrypted (LUKS) root partition(pre- mounted configuration), the installer showing the error:

"Invalid configuration: root partition not found"

This happens even though the root partition is correctly opened, formatted, and mounted at /mnt, and the EFI partition is mounted at /mnt/booti.

Manual verification confirms that the root filesystem is present and accessible, but archinstall fails to detect it.

Please let me know if there is any solution to this problem. I am unable to use my PC due to this.