Lacerte will only calculate the OSTC other state tax credit if the client is a full year resident.

I have the same situation.  OSTC is not showing up on return for income taxed in Georgia.  Full year Ohio resident is checked.  Need to complete Ohio Form IT-RC, but can find an input screen and "jump to" feature is not available.

Is this for tax paid to another state via a composite nonresident return?

Several people have reported that they can't this to work for OH.

EDIT: Or was this a ProSeries isue?

No, it is for a Georgia return prepared for the taxpayer on Lacerte along with the Ohio return.  I found another post that "fixes" the problem, but there is no logic behind the fix.