I've noticed the same thing for LinkedIn, etc corporate communications. All of a sudden every CEO and marketing leader is packing them in.
And those stupid stylised "fonts" that create problems for screenreaders by using obscure Unicode characters.
Are you saying they are adapting them in a kind of cultural adaptation to the ChatGPT outputs, or are you implying the higher likelihood that they sees simply unquestioningly posting/sending AI outputs?
I remember going away from youtube for a month right before it added buttons for quick emojis to its app (summer 2022 iirc?)
returning to it getting filled with emojis was bizarre - but it largely went away now