Fix bsdinstall "Auto (UFS) Guided Disk Setup" and sade(8) "Auto" button.
Probably this should solve: https://lists.freebsd.org/archives/freebsd-current/2022-April/001851.html
I had a different error message during installation (bsdinstall/partedit) and a segmentation fault with sade locally.
Problem causes: 1) dialog does not differentiate between form.init and form.value, 2) dialog always allocates memory for the value while bsddialog only when a key is pressed.