I tried exporting a 1920x1080 29.97fps project to Blu-Ray in PS24 legacy mode.  The video stuttered on playback on both my Blu-Ray Players.  PS24 exports the same project to 1920x1080 29.97fps 64mbps MP4 file that plays fine and as a movie file on the DVD player. I took the exported MP4 file that I made with PS24 and placed it on the PS24 project timeline.  I tried creating a Blu-Ray, it still stutters.  I took the same exported file on the timeline of PS21.5, made a Blu-Ray and it plays fine.

Video of playing the m2ts files from each Blu-Ray image:

http://www.acscontrol.com/ps/PS24Blu-RayPlayStutter.mp4