Apple's keyboard likes to hallucinate weird results (like changing out common words for names of people I don't even have in contacts) and edit after the fact.
Never seen that on any of the iPhones in my family, and never heard of that happening on any of my friend’s iPhones despite being the usual tech help contact for them. And this is going back to 2012.
Maybe take it to a Genius Bar and have them correct whatever strange problem that is.
Because that kind of behaviour is extremely unusual.
