This has nothing to do with cache or not being able to click the "Switch to Classic View" button.  If all you had to do was click it 1-time, sure, no big deal.  You have to click it repeatedly, every time you click a transaction in classic view and go back, you are back in Modern view.  And it is literally impossible to get back to the initial report, it just puts you in an endless loop of going back and forth between classic and modern view until you open an entirely new report.  This is the worst update QBO has ever made.