How do I fix the problem where every time I enter US government income for a mutual fund, Turbo Tax erases it without an error message?

other mutual fund accounts that had US government income did not have this problem.   After I enter the $ amount it puts me back on the page with all the 1099-Div accounts but it says it needs review. If I uncheck the box that says US government income is included, then everything works fine, so I assume that it doesn't like the interest.  Info from the 1099-div was imported directly from the mutual fund company.