In case anyone searches and finds this post:
This particular SQL cluster is our largest, with two SQL instances and dozens of databases. We back up transaction logs every 15 minutes, and we do this via one job for each database for each instance. Similarly, we have one nightly job that performs a full backup of all databases in both instances.
Whenever double-clicking a backup to restore, SMSQL enumerates each backup for each database, not just the one backup we want to restore from. This is 100+ databases x 96 backups and SMSQL cannot keep up. NetApp Support has indicated this is a known issue and they are working on a redesign to address it.