This was the actual e-mail, as you'll see it's link free. I went to the site and the same thing popped up when I signed in:
As part of our security measures, we regularly screen activity in the PayPal system. During a recent screening, we noticed an issue regarding your account.
We have reason to believe that your account was accessed by a third party. We have limited access to sensitive PayPal account features in case your account has been accessed by an unauthorised third party. We understand that having limited access can be an inconvenience, but protecting your account is our primary concern.
Reference Number:
For your protection, we have temporarily limited access to your account. We will review this access once you have completed all the steps we have requested. You can view these steps in the Resolution Centre of your PayPal account.
To review your account and some or all of the information that PayPal used to make its decision to limit your account access, please visit the Resolution Centre. If, after reviewing your account information, you seek further clarification regarding your account access, please contact PayPal by visiting the Help Centre and clicking 'Contact Us'.
Thank you for your prompt attention to this matter. Please understand that this is a security measure intended to help protect you and your account. We apologise again for any inconvenience this may cause you.
Sincerely,
PayPal Account Review Department