Why is My “Price as at” a Future Date, but There is not an Entry for This Date in My Stock Price History Table?

your Price data structure may need to be refreshed. You can do this by either pressing [CTRL]+U or going to Home -> Database -> Rebuild.

Doing so should remove any pieces of incomplete or incorrect data (which has been downloaded from the Data Downloader). You should now be able to utilize the Data Downloader to correctly download the prices for the stock in question as normal.