I got something exactly like that (right down to the same wording) from a local (Massachusetts) credit union about a year ago.  Thought it might be a phishing scam & waited for a follow-up email from them, but  didn't receive anything more.  Probably phishing.  Also got a phone call one evening from someone who said they were calling from my bank & that there was a freeze on the account due to some sort of error (they wouldn't say what) & interestingly enough they had all but the last 3 numbers of my checking account & they wanted me to fill in the numbers for them (to "prove" that it was my account).  I asked them if they needed my social security number as well & I could practically hear them drooling over the phone line.  Clearly a fraudster so after telling them that I had to get my social security card out of my wallet in the other room, & leaving them hanging for 20 or so minutes, I hung up the phone & called my bank in the morning to sort it out.