Thank you for the reply. Yes I have tried restarting in safe mode. The messages do not appear in the console when I am in safe mode, but return when I log back in normally.
Here's the behavior I witnessed: I purchased an app from the app store by tapping on the "price" button and then "buy". The Buy button turned into the round progress button with the square stop in the middle and it started to install, right as it got to end (circle fully completed) the progress disappeared and turned into the "price" button again. I clicked it again and it said I had already purchased and it would re-download. That did not happen. After a few restarts and a log in/out the app showed up in my purchased items (with the cloud/down arrow button). I clicked that to install the app and it fully download and then just hung -- in the app store the circle progress was 100% but not changing to "open" and in the launchpad it showed the progress bar underneath and inside the launchpad showed the app icon grayed out and "installing..." underneath it. It stayed like this for at least a half hour with a 7.5mb app. ...and the error started in the console and ran every 10 seconds:
ReportCrash (AppStoreFoundation)
Subsystem: com.apple.appstorefoundation
Activity ID: 0 Thread ID: 0x316f PID: 373
Invalid receipt [0 bytes]
Sorry for the rambling. To answer your other questions the App Store is otherwise running as normal, no error messages at all and I was able to purchase and install a different app after this situation.