Interestingly, I did HP5 to full disc BD-25 quite some time ago, and it worked perfectly.
So I load BD-RBV03708, and it shows "Approximate Source Content: [ 5:03:47.266]. However, the main movie, 00000.m2ts, is not in the list of streams to be reencoded.
If I switch to Movie Only mode, then it is listed as well as the three alternative mpls files for 00000.m2ts ( 00000mpls, 00059.mpls, and 00060.mpls ) for a movie length of 2:18:14.452.
HP5 does have 14 listed audio tracks available for the main movie, of which two are English; one is LPCM 4608kbps and one is 640kbps 5.1 DD.
The largest listed stream to reencode in full backup mode is VID_00031, an MPEG-2, 480i 29.97fps stream, and the next largest is VID_00002, which is a VC-1, 1080i, 29.97fps stream.
So it does appear their is something not right.
If I click Backup on the above listed attempt, I get Target is too small to continue!