Specifically for framerate-adjusted and remuxed "The Appendices - Part 3.mkv" in The Hobbit Trilogy All the Appendices Bonuses and Extras 720p Bluray HEVC 10Bit DD2Ch-ShieldBearer. This corresponds to Part 9 when including the first 6 Appendices from LoTR. Thanks Gaszpode: "...the offending file needs to be put into MKVToolNix, select the video track, and then set the 'Default duration/FPS' option on the right-hand side to 24000/1001p"