LiteSpeed fast compression backup of TDE databases are not being compressed. I'm running LiteSpeed 8.8.0.376.

LiteSpeed fast compression backup of TDE databases are not being compressed. I'm running LiteSpeed 8.8.0.376.
With xp_slsFastCompression:
     Native Size: 2688.63 MB,
     Backup Size: 2684.95 MB.
I tried Compression level 2, 3, and 8. I also tried Adaptive Compression = Size.
But using xp_backup_database it does compress:
    Native Size: 2691.25 MB,
    Backup Size: 560.57 MB.