BLANKING of password fields (instead of showing the dots) in iPhone screenshots

Is the following a bug or a feature? On my iPhone, I take a screenshot of my mail settings while setting up a new mail account. (If you are desperate to know why, you can read the paragraph below.) I can see with my eyes that there are dots in the password field, the usual dots that are supposed to appear there to obfuscate the password that I just typed in myself. But does the ***screenshot*** show the dots?!?! No. There is an empty-looking field instead. So the screenshot does NOT exactly match what I can see.

Surprise! A screenshot isn't what I thought it was, not like a screenshot on the computer.

What I need is someone official from Apple to respond to this question so that I can prove that my phone isn't broken, that this is expected behaviour (a feature) not a sign of ill-health of my phone (a bug).

Why? Because I am trying to get help from my email provider who is convinced that my iPhone isn't working since it looks like there is nothing in the password field when I send a screenshot. When setting up the account, there was an error message that mentioned passwords. Now they are dogs with a bone. They will not help me get my email working until I "fix" my iPhone. They are convinced they have received 10000000 screen shots from iPhones with dots in them in the password fields from other customers. They are convinced mine is the only iPhone doing this. Unfortunately, it isn't the things we don't know that get us in trouble. It's the things we are convinced are true that are false.

Apple should document this at least in the Senior Advisers kbase. Senior Advisor couldn't even find an article.