These occur if you've already entered transactions into your Money account and then import a QIF file containing the same transactions. When reconciling, you can view and remove these duplications.
These can also occur if a QIF file is imported after your bank statement is printed (for example, the QIF file may have cleared transactions that aren't on the bank statement). When you reconcile your Money account with the imported QIF file, mark the imported transactions as uncleared. This will help you if you choose to balance your account with your bank statement.
The QIF file format does not include account balance information. Money will be unable to display a balance for these statements.