No, this is real. I had several domains at Hover and I’ve been moving them to CloudFlare because it is cheaper and provides services (free) that Hover doesn’t provide.
So I’ve gotten these before. First time, I called Hover and eventually got to someone that confirmed my domain was no longer with them, but their system doesn’t know that and I can just ignore the warning about the domain expiring.
Needless to say, that confirmed my experience that their service and support has gone downhill since the early days when they were a refreshing alternative to GoDaddy or other churn factories.