After I drill down in classic view in B/S or I/S, when I go back after drilling down, it reverts to modern view. I want this to stop. It didn't used to do this.

QuickBooks updates the reports' interface defaults to the modern view, @TRyan1.

In QuickBooks Online, Balance Sheet and Profit & Loss reports default to the modern view. After drilling down and clicking Back to report summary, it returns to the modern view because QuickBooks treats it as a new action.

Since we are gradually moving all Standard Reports to the Modern View and removing the Classic View, eventually switching between the two views will no longer be an option.

To avoid switching views, you can open drill-down reports in a new browser tab. You can right-click on the link and select "Open Link in New Tab". This keeps the classic view open in the original tab.

Don't hesitate to comment below if you have further questions about the new QuickBooks interface.