On my Intuos5 tablet, flipping the pen around to the eraser tip activates eraser mode, as expected. However, flipping the pen back to the drawing end causes the erase mode button to flip back off, but actually drawing with the pen down erases instead of draws. I have to press "e" to manually turn off erase mode (the state of the erase button does not change when I do this).

I don't think this is a driver issue, as the eraser tip works as expected in Xournal, and it also worked in Krita until I updated to 3.1.2 a couple days ago.