Make Blu-Ray wants Double Layer DVD for 2.5GB BD video

I generated an HD Blu Ray disk from FCP and Compressor. The resulting DL disk only used 2.5 GB. Create Disk, the Compressor post processor to burn the Blu Ray disk would only accept a double layer DVD, in-spite of the relatively small BD video size.

The video was compressed as H.264 and Dolby surround.

Any suggestions?
Rick