When your device is in landscape orientation, it shows two pages side by side if there is room. Since you can only zoom or annotate on one page at a time, you must select the proper page before using the toolbar. Depending on which page you tap, that page will be selected in the toolbar.
Tap a page to select it.
The tools will work for whichever page you select, so make sure to tap on the actual page you want. In the above screenshot, I've tapped on the right page, which is why "God Is Able" is shown in the toolbar.