SQL Server Transaction Log VLFs not being released (Status 2) on log shipped Database

Have seen a couple of posts similar to my scenario, but nothing that actually resolves my issue.

Scenario:

• Routine index rebuild happens, once a week, 2 AM Saturday morning.
• Log file grows about 15x the usual size.
• Transaction log backup is taken (every 10 minutes, 24 x 7).
• FULL backup is taken every day at 3 AM.
• VLFs are remaining "active" (status 2) when i look at dbcc loginfo
• log_reuse_wait_desc is reporting "LOGBACKUP" in sys.databases
• dbcc opentran is reporting no active transactions
• @@version: Microsoft SQL Server 2005 - 9.00.5069.00 (X64) Aug 22 2012 18:02:46 Copyright (c) 1988-2005 Microsoft Corporation Standard Edition (64-bit) on Windows NT 6.1 (Build 7601: Service Pack 1)

Problem:

So, my issue is simple, because of hardware restrictions and time parameters, i need to keep transaction log size as small as possible. i believe the reason it is not releasing the space is because the VLFs are active and it thinks it needs to take a LOGBACKUP to release, but after countless log backups, the log_reuse_wait_desc is still reporting awaiting a log backup!

I could change the recovery model to simple, shrink and change back, but this breaks my LSN chain and my Log Shipping implimentation, so its not really a viable solution!

TIA.