No way to know.. a few others have had this problem.
1) Try a Copy & Paste to the field
2) Try a full computer reboot if that doesn't work.
3) Finally (sigghhh)....Customer Support:
What is the TurboTax phone number? (intuit.com)
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*