I have had a couple of such emails in the last few months and they state ebay has protected my selling account, this time they have "Removed 1 transaction defect(s) from your seller dashboard". But I wasn't even aware of there being a defect in the first place. The one before was in a similar manner of them having done something to protect my dashboard, but again, I had no idea that there had been an issue in the first place as I didn't have any emails or anything telling me that I did.
If anyone knows or has dealt with these emails, some explanation would be fantastic!