Heck AC has been poor for many iOSes.
It’s an absolute embarrassment. The worst thing about iOS and macOS too. In a way it’s like siri. Impressive when it first came out many years ago but hasn’t advanced and sometimes it goes backwards.
it’s quite common for me for the iphone or Mac to invent autocorrections like the OPs yes problem. They annoy for a while and then go away.
But there are so many basic problems with apples autocorrect.
Firstly it doesn’t actually pick up on most of my genuine typos. You know when you type an 8 letter word and there’s one letter wrong so it’s clear to a child that it’s a typo. No instead the phone or Mac will swap 5 letter words for entirely different ones just so it thinks it’s clever for pointing out that the new word is one letter to the left of mine on all 5 letters.
When I type a correct word and it autocorrects it to a wrong one or (and I have sympathy the first time ) when I type a foreign word or place or brand name and it autocorrects to something else and I go back and change it back to what I typed originally don’t change it again! I know on the Mac I can hit escape but what should I have to ?
And once you take the step to fix the basics apple , then be positive and make it great. I have a powerful Mac and iPhone that could fly a spaceship to the moon. Let them react intelligently and learn. Notice that I often type Portuguese words and don’t autocorrect them.
Notice when I’m typing and I’ve typed a lot of foreign place names so I’m clearly talking about Thailand so don’t autocorrect anything that’s a place there for the next 10 mins.
Realise that whenever I’m in a certain web page and I use the search box that it’s always authors names so don’t autocorrect to words in that specific search box.