Hello Matt_Hale
This EVA 4000 (HSV200 is EVA4000) has mis behaving backend device and that is why we are seeing this behaviour. It could be a drive, cable, IO module or even any of the controllers.
When the device is misbehaving, the loop will be down (you will see the port errors for the respective controllers) and the loop cannot be enabled until the issue is fixed. And, since the loop is coming back automatically (the controllers will retry enabling the loop in the background periodically), it appears the issue getting cleared intermittently.
Only the analysis of the controller event logs can clearly tell what is happening. The command view EVA is of little help in troubleshooting intermittent loop issues.
You should reach support if the array is too critical for you since such issues may end up in a complete array down scenario if not treated in time.