What is this chat new warning pop up

I opened a chat window on "chat" option of an item I am interested in and click the back button too fast to read a warning or safety message bthat poped up. I was messaging someone in a different city if that matters. I assumed it was spam ads, but the part I was able to read looked like an important safety warning. Does anyone know if a new patch has a similar message pop up/know the contents of it? Thank you