This happens to me all the time (it's OK I believe anyway). Always use the same desktop computer, Chrome, Windows 10. Everything is updated & no extensions. I clear cache/cookies once or twice a day.
When I Sign Into Etsy, I get a red banner "an error has occurred". I Refresh Pg. and I'm in. (At one point I was getting the Captcha Pg. intermittently. Haven't had it since June 21). When I leave Etsy, I first Sign Out of Forum then out of Etsy. I get an Email (the one you stated): "Did You Recently sign in to Etsy?" (followed by device, browser, OS, City/State, etc.). And "Disregard this Message if you did".
When I am IN Etsy > Account > Security (I believe): It shows all my Sign Ins. Every single one of mine is the same (I never deviate fr. this desktop computer). And it SHOULD be the same. If it isn't, someone else has used the computer who shouldn't. So it's a security check to make certain no one but you has gotten in. If I see something on that Sign In Page that isn't my computer, browser, OS, etc. I'd want to know. And I'd better not ever see that.
Hope this helps you.
ETA: Personally I would want that Notification Email (for the purposes I mentioned above). I just look at it and delete.
