It would appear that the 8K sample has been encoded using regular VP9 and not VP9.2: -
Code:
[info] Available formats for 1La4QzGeaaQ:
format code extension resolution note
249 webm audio only DASH audio 58k , opus @ 50k, 2.01MiB
250 webm audio only DASH audio 78k , opus @ 70k, 2.68MiB
140 m4a audio only DASH audio 130k , m4a_dash container, mp4a.40.2@128k, 5.21MiB
251 webm audio only DASH audio 150k , opus @160k, 5.29MiB
394 mp4 256x144 144p 90k , av01.0.00M.08, 30fps, video only, 3.11MiB
278 webm 256x144 144p 98k , webm container, vp9, 30fps, video only, 3.65MiB
160 mp4 256x144 144p 111k , avc1.4d400c, 30fps, video only, 2.67MiB
395 mp4 426x240 240p 221k , av01.0.00M.08, 30fps, video only, 6.84MiB
242 webm 426x240 240p 226k , vp9, 30fps, video only, 7.62MiB
133 mp4 426x240 240p 245k , avc1.4d4015, 30fps, video only, 5.70MiB
330 webm 256x144 144p60 HDR 245k , vp9.2, 60fps, video only, 8.88MiB
396 mp4 640x360 360p 392k , av01.0.01M.08, 30fps, video only, 12.27MiB
243 webm 640x360 360p 411k , vp9, 30fps, video only, 14.34MiB
331 webm 426x240 240p60 HDR 499k , vp9.2, 60fps, video only, 18.95MiB
134 mp4 640x360 360p 633k , avc1.4d401e, 30fps, video only, 17.17MiB
397 mp4 854x480 480p 720k , av01.0.04M.08, 30fps, video only, 22.33MiB
244 webm 854x480 480p 774k , vp9, 30fps, video only, 26.52MiB
332 webm 640x360 360p60 HDR 1061k , vp9.2, 60fps, video only, 40.88MiB
135 mp4 854x480 480p 1352k , avc1.4d401f, 30fps, video only, 35.62MiB
398 mp4 1280x720 720p60 1511k , av01.0.08M.08, 60fps, video only, 45.35MiB
247 webm 1280x720 720p 1571k , vp9, 30fps, video only, 54.04MiB
333 webm 854x480 480p60 HDR 2022k , vp9.2, 60fps, video only, 77.41MiB
302 webm 1280x720 720p60 2664k , vp9, 60fps, video only, 91.20MiB
136 mp4 1280x720 720p 2698k , avc1.4d401f, 30fps, video only, 70.39MiB
248 webm 1920x1080 1080p 2762k , vp9, 30fps, video only, 95.02MiB
298 mp4 1280x720 720p60 4201k , avc1.4d4020, 60fps, video only, 115.83MiB
303 webm 1920x1080 1080p60 4460k , vp9, 60fps, video only, 156.50MiB
334 webm 1280x720 720p60 HDR 4521k , vp9.2, 60fps, video only, 177.79MiB
137 mp4 1920x1080 1080p 5065k , avc1.640028, 30fps, video only, 130.40MiB
335 webm 1920x1080 1080p60 HDR 6907k , vp9.2, 60fps, video only, 272.04MiB
299 mp4 1920x1080 1080p60 7008k , avc1.64002a, 60fps, video only, 204.40MiB
271 webm 2560x1440 1440p 9107k , vp9, 30fps, video only, 299.22MiB
308 webm 2560x1440 1440p60 13297k , vp9, 60fps, video only, 461.27MiB
336 webm 2560x1440 1440p60 HDR 16269k , vp9.2, 60fps, video only, 643.16MiB
313 webm 3840x2160 2160p 18217k , vp9, 30fps, video only, 642.40MiB
315 webm 3840x2160 2160p60 26604k , vp9, 60fps, video only, 996.25MiB
337 webm 3840x2160 2160p60 HDR 28928k , vp9.2, 60fps, video only, 1.12GiB
272 webm 7680x4320 4320p60 32524k , vp9, 60fps, video only, 850.48MiB
43 webm 640x360 medium , vp8.0, vorbis@128k, 33.32MiB
18 mp4 640x360 medium 674k , avc1.42001E, mp4a.40.2@ 96k (44100Hz), 27.15MiB
22 mp4 1280x720 hd720 1877k , avc1.64001F, mp4a.40.2@192k (44100Hz) (best)