Some hosts are accessing LUNs via non-optimal path (path to partner head). While it may seem to not have immediate impact, it means that
- There are some performance implications because all requests go via NVRAM/cluster interconnect
- There may be high-availability implications; may be this is the only remaining path so losing it means completely losing access to data
The reasons vary from misconfigured host to faulty hardware; if you are not sure how to approach it open support case with NetApp, they will guide you.