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