Hello. My name is Michael. I will assist you with your question.
Pandora works over the USB connection when you run the native Pandora app on the iPhone because it knows to use the "portable player". But it does not output sound when connected to the USB connection when you run the rav4 Entune app (which uses your phones Bluetooth connection and is controlled through the rav4 touchscreen). Entune uses the Bluetooth and your phone's cellular connection to download data to the entune native pandora app. The phone itself does not output sound because it is used solely as a data connection for the rav4 apps... But since you are connected via USB there is a bug in the rav4 radio which thinks that it needs to pull sound from the iPhone which is only used for data. Thus there is no sound. When you pull the iPhone off the USB connection, it plays audio correctly via the Bluetooth data connection.
I would expect that it was behaving in a similar fashion prior to the update.