FYI, I get exactly the same error that you and since 10 days, it happens more and more. The only way to solve it to restart the application.
Also, I have already disabled IIS overlap recycling (https://stackoverflow.com/questions/27421024/disable-pool-recycling-on-azure-websites)
But the issue still appears this morning.
Does nopCommerce is working on this issue ? This is really problematic to not have any way to fix it. Client are becoming upset unfortunately ...