Bold letters and statements

Hello co teachers,

I've tasked my students to submit an essay and there's one trend that keeps appearing. There's an unusual amount of bold letters and statements. I know a bold text signify their importance but it's the first time I've seen students use this style of writing, and worringly a number of student's submissions are like this.

I would like a genuine and honest opinion, have you seen this in your class as well? Should I be concerned that my students are using AI in creating their paper?

Your insights would be most fruitful, thank you!