Agree with you the input is not the most intuitive.

But if you had checked the return and reviewed IT NRC, which is where the residency info is reported, you should have noticed that the input is for the other state's residency period rather than OH's and that ProConnect Tax would subtract that to arrive at the OH residency period to show on the form.  You wouldn't then have to wait for the return to be rejected to find out.

Ultimately, it's PBKAC.