How do I get Form 5329 in TurboTax Premier to accept my explanation text

I am attempting to manually complete form 5329 in TurboTax Premier 2025, for a missed 2025 RMD.  I have entered the missed RMD amount on line 52a, and wish to request a waiver of the penalty. I am working in the "Waiver of Tax Smart Worksheet", and was able to enter the dollar amount for which I am requesting a waiver.  HOWEVER when I select the + sign to add my waiver explanation text, and continue with my review, I get an error and TurboTax "thinks" the explanation field is not completed. When I re-enter the explanation text during the review process and select "continue", the text is again lost by TurboTax, and an error is again reported.  I cannot eliminate this error, and get TurboTax to retain my explanation text and include it in my return.