I got the same. I first thought it meant that I was banned. Happy to hear that I am not alone.
(The timing really was in support of my paranoia. Yesterday I did a bulk retrieval of workouts from my Garmin account to my Runalyze account, using a tool not supported by Garmin. So when I saw the words "cross-user" - which could be interpreted as a user making a cross connection to Runalyze? - and the word "banned", I thought: "Ouch, Garmin didn't like what I did, and now they banned me.")