Box 1f relates to an accrued market discount. Given that your Box 1f contains a 0, have you tried leaving box 1f blank rather than inserting a 0? Sometimes entering a 0 interferes with the calculations.
When you enter your RSU information, if you do not check the box "I have other boxes on my 1099-B to enter," then Box 1f and Box 15 will not appear. Because Box 1f has a 0 amount, and Box 15 is blank, try unchecking this box and see if that corrects the error that you are confronting.
@Klewisx333
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