We just received the same alert on two of our Unity units today but status is healthy. May open a support ticket to see what's up. 

Any updates to this?

I opened a support ticket and was told the alert is benign and to clear it. Here's an article they sent, a fix has already been pushed out so you just need to go in and clear the event. 

https://www.dell.com/support/kbdoc/en-us/000376718