Identifying the correct BD playlist using BDInfo
BDInfo is a really useful little tool & is a free program -
Play your blu-ray title on your set top player and note the total time and chapter count. Then use BDInfo to examine the video playlists and .mpls videos from the title to determine which playlist is correct. Multiple playlist entries with the same length and chapter could be legitimate, could have different angles to accommodate language choices (showing french titles with a french language choice, for example) or could just be the movie studio playing games to foil folks who want to rip and watch their movies off their servers. Once you identify that some further analysis is needed, your best bet is to compare the contents and sequence of the video files referenced in the playlist that match your time and chapter count and look for where the movie studio is playing games. There could be unique incorrect inserted video files, video files out of sequence, etc. BDInfo has a built-in report capability that is very useful for this purpose.
You could also do some googling of the title and hope someone else has done all this work for you . . . but be careful that someone isn't posting information about a rental version of the title that may not match your purchased retail version.