iPhones can definitely garble text, although it's not clear whether they can substitute some text for another. Seems possible but unlikely (in a purely statistical sense).

https://www.reddit.com/r/iphone/comments/1m5zsj7/ai_photo_ga...

https://www.reddit.com/r/iphone/comments/1jbcl1l/iphone_16_p...

https://www.reddit.com/r/iphone/comments/17bxcm8/iphone_15_n...