iPhone always wants to change my email address

There is, embedded deep within the bowels of my iPhone settings, something that causes my phone to want to replace my email address with the string “xxxz”.

originally, I thought this had something to do with Safari but tonight I learned that’s not the case. I was typing my email address into a text message and as soon as I finished typing it, up popped a string offering the “helpful hint” of changing my address to “xxxz”, with xxxz being the default option, as in spellcheck. Apparently, this happens whenever and wherever I type my email address. How can I get rid of this unwanted “assistance”?