Forms folks buy off the shelf for a will often fall into this category. That is why a valid will should be prepared by a skilled attorney INSTEAD of a self prepared will.
A valid will does accomplish the goals of the person making it. An invalid will like the one you describe is worthless.
The will signing ceremony appears to be what went wrong. The witnesses must do a solemn attestation, and other Minnesota state law rules must be followed, to. Without a full compliance with the law, the self made will fails.