My keyboard types the wrong key. For example, I press shift and the question mark and onscreen I get an underscore.
It i
iPad Pro 11-inch Wi-Fi
Question marked as
Go to settings > general > keyboard > Hardware Keyboard and tap over at the right edge. Make sure you have chosen US or ABC (and NOT "automatic" or Spanish ISO).
(If Shift ? produces _, that indicates you may have the Spanish ISO layout active by mistake)