Something similar happened when Ohio was admitted in 1810. The error was discovered in 1950 and corrected by the Ohio Legislature.
Many states were not legally admitted.
New states have to be admitted on the same basis as (and with equality to) old states.
That means, among other things, that the federal government cannot attach conditions to a new state as a basis for its admission.
(Oklahoma wanted to be admitted but the feds insisted the state capital be at Norman, and not Okla. City. That federal condition was ruled to be invalid and illegal.)
Most western states were admitted under the condition that vast areas of their lands remain under federal control. (The most blatant example is Alaska.)
However, those conditions were (and are) illegal.
Ergo, either those conditions are invalid; or else the ‘conditional’ admission of those states was not legally valid.
Funny that Ohio is called the “Mother of Presidents.”