According to document 357546, installing SP4 or HF 351848 for Backup Exec 12.5 causes GRT Exchange restores from Tape to no longer work. The same article documents the same issue for other versions of Backup Exec (11, 12 and 2010) as well. There is a documented fix for 2010, but nothing listed for the other versions. The only workaround is to Duplicate the backup set to disk, and then perform the restore.
My question to Symantec: Are you planning on fixing this in 12.5? When might that fix become available?