Thank you. I have made the change, and so far LUN discovery seems to be reliable. I've done a bunch of refreshes on the cluster (under hosts -> disks view), and whereas before they used to occasionally show me three LUNs instead of five, now I get all five every time. The last ten log backups also run successfully - a longer streak than I ever got before.
Just out of curiosity, where is this documented? Is it something available to customers, or only internally to NetApp support?