I can only guess that a bad (zero) price quote has been downloaded for Friday, Oct. 13th.
For each security that has bad prices edit the price history and either delete the bad price record or change it to the correct closing price.You can also use the Investing Tab's Portfolio view, set to "As of Date: 10/13/17" and directly edit the price quote to update it to what it should be.
Carol, when you look at your Bonds in the Portfolio view what do you see Oct 13?