TrueHD sample that shows same behavior. Maybe it happens with all real 24 bit tracks...
Code:
eac3to aaa.thd aaa.flac
TrueHD, 5.1 channels, 48khz
Decoding with libav/ffmpeg...
Encoding FLAC with libFlac...
Creating file "aaa.flac"...
The original audio track has a constant bit depth of 24 bits.
Superfluous zero bytes detected, will be stripped in 2nd pass.
Starting 2nd pass...
Decoding FLAC...
Encoding FLAC with libFlac...
Creating file "aaa.flac"...
eac3to processing took 9 seconds.
Done.
eac3to aaa.flac
FLAC, 5.1 channels, 0:00:36, 24 bits, 2051kbps, 48khz