I have HiDef footage that I edited and exported from Premiere CS3 to Encore CS4 using the BluRay High preset.

NTSC, 1440x1080, 23.976 [fps], Progressive
PCM Audio, 48 kHz, Stereo
VBR, 2 Pass, Target 20.00, Max 25.00 [Mbps]

Premiere asked me to save the file and it exported the file as .m4v for video and .wav for audio. Once AP finished transcoding it opened the Encore. Both files are shown untranscoded under the BR Transcode Status column. I transcoded the .wav file, but when I try to transcoded the .m4v file I get the following message:

The file you about to transcode is already legal for Blue-ray. Transcoding will affect its quality.

I click cancel in the dialog, but when I try to build a blue-ray folder Encore starts building with transcoding the .m4v file.

Why is En start transcoding if it just told me that I do not need to? Is there a setting I am missing?