Received a message with `other` as both Subject and message body.
After opening the site I noticed the notification for reaching the 10 star threshold on TopTex, so that was probably the reason for getting the email.
Note: this is similar like this previous bug report, but the cause is different than indicated in the answer there (I hope): https://topanswers.xyz/meta?q=2041
Thanks for reporting this - I've given system notification emails a proper subject and body.
You should get your recent 10 star notification again in the new format