QCD Entry

I have received a 1099R that contains a portion of which is a QCD.  The sender has indicated that the taxable amount is not determined. Regardless of my entry to to boxes 1 and 2a, it does not change the taxes that are being calculated in Turbo Tax; I have even dropped it down to 25%. The sender has indicated that the use of the code "Y" was optional for 2025. The sender also sent the form with a 7 in the Box 7.

If I change box 7 to a "Y" or add a second code and put a "Y" in that 2nd box, Turbotax calculates an extremely large amount that I am sure is incorrect. Is the programming working correctly?