For most of us it is quite difficult to understand, we have already taken our finger off the caps lock key before we carry on typing.
For the people who are having a problem, they are obviously hitting a key before they take their finger off the caps lock key. I cannot replicate this error with any kind of normal typing behaviour, this is why I printed a slow typing test where you deliberately put your finger on and hold the key.
There is no such thing as a simple keypress, you must first press down a key and then you must release a key. Most folks never notice.