Hazard symbol next to received PM?

[Letty]

Just a quick question--I received a PM from someone last night, but the message they sent has a little exclamation point/hazard symbol next to it in the inbox, similar to the symbol used for reporting messages? I definitely didn't report the message, so does anyone know what it means? I couldn't find any information on it elsewhere on the site unless I'm missing a really obvious location for the explanation.

[Eagle's Eye]

I think you're talking about the PM icon. You can see the choices of PM icons when you go to a compose message page

[Letty]

Oh, you're right, thank you! Maybe it's possible I hit it with my thumb while replying to the message on my phone? I assumed it meant something was wrong since it looked like a warning sign, so I'm glad it's just an icon!