[wlesieutre]

Is predictive text the one that reaches back and changes correct words that I had already finished typing?

[malfist]

Man, gboard does that on android so much that I wound up installing and using heliboard. It kinda sucks but at least it doesn't "fix" your message after you type everything

[sbdaman]

It predicts what you are going to type as you type. It has a tendency to add words to the end of a message when you hit send.

[washadjeffmad]

Whatever it is, it's bad on GBoard, too, if you possess better than a 6th grade vocabulary.