I have now had one every day since the feature was introduced - and it's me every time and the information is the same as it has always been.
I was about to open a Support request as I was getting a wee bit tired of it only to discover it is a known issue - a lot of users are getting this email and LJ are reviwing the settings for the feature and will be adjusting it.
I clear all date, history, cookies, etc. etc. every day and I wonder if that might have something to do with why I'm getting them? If anyone else on my flist are getting these emails regularly, may I ask do you clear history, cookies, etc. every time you log off?
That aside, if you are getting these emails and wondering why and/or worrying even that someone might be logging in as you, rest assured it does seem to be a 'glitch'.