It should say who exited it. either you or one of the mods/admin. If it says you then maybe you hit the edit button and then just hit save. It would show as exited by you regardless of whether or not you changed anything.
That's odd. I'm inclined to think it's user error... that maybe you accidentally clicked the edit button and then tried to close out of it quickly, but clicked "save" instead of cancel, resulting in the stamp. I have done that before. I do all kinds of bizarre stuff, especially when I'm using my phone. Just last weekend I went to approve a new account. My admin screen gives me a few boxes I can edit, including their name and e-mail address, as well as check boxes to approve the account. Well, I glanced at the email box and it had MY email address in it. I exited out and went back in. It still had my email address. I spent like 10 minutes going through all the settings getting all crazy paranoid- who was this person, how did they have my email address, and how did they manage to get through the email validation process with my email??? Then, it hit me. My phone was trying to auto-fill it for me. Every time I opened the screen, Apple was being oh-so-helpful by inputting my own email. Thank you, Apple.
Anyway, if it was a mod who edited it, it would have stamped one of our names. Even I can't change that setting. I suppose it's theoretically possible some kind of glitch did it, but unless other reports of similar issues start coming in, it's likely you unintentionally triggered it. I'm not saying 100% it's your fault, but...
Umm yeah, that happened to me once it was a post that was more than a year old and I didn't touch it and it didn't look like it was changed.
I was worried someone else signed into my account cos another weird thing about AM is you can sign into Benedict Arnold's account! If you log out and there's a number above that little bell at the top of the screen after you log out you can click on it and you're in Benedict Arnold's account! Yeah, strange but true! Hmm, I hope that doesn't work for anyone who isn't Benedict Arnold, lol!
I just tried that and it didn't work... It logged me out and flashed my notification count for a second, but that's it. I can look at the notification screen for BA if I type it into the address bar, but it's rather ho-hum. Was that your experience or did something else happen? What browser do you use?
It shows me all of Benedict Arnold's notifications so I like to click on them to read the posts to find out who the Arnold was but it doesn't let me do anything else like accept friend requests on Benedict's behalf cos it kicks me out when I try that.