Can't find who asked me to test this in which forum, but the 4K 3D FSBS 'Superman' sample (re-uploaded here) plays just fine. Hope you happen to be checking here 
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Code
General
Unique ID : 185180053044970592874442986220935700675 (0x8B5061846204EEC5AEF1267E6AABE0C3)
Complete name : Z:\Various\Superman_4K_SDR_Sample.3D.SBS.mkv
Format : Matroska
Format version : Version 4
File size : 1.26 GiB
Duration : 1 min 3 s
Overall bit rate : 170 Mb/s
Frame rate : 23.976 FPS
Writing application : Lavf60.3.100
Writing library : Lavf60.3.100
ErrorDetectionType : Per level 1
Video
ID : 1
Format : HEVC
Format/Info : High Efficiency Video Coding
Format profile : Main@L6@High
Codec ID : V_MPEGH/ISO/HEVC
Duration : 1 min 3 s
Bit rate : 166 Mb/s
Width : 7 508 pixels
Height : 2 160 pixels
Display aspect ratio : 3.476
Frame rate mode : Constant
Frame rate : 23.976 (24000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.428
Stream size : 1.23 GiB (97%)
Writing library : x265 3.5+93-a7eebdabb:[Windows][GCC 12.2.0][64 bit] 8bit+10bit+12bit
Encoding settings : cpuid=1111039 / frame-threads=3 / numa-pools=12 / wpp / no-pmode / no-pme / no-psnr / no-ssim / log-level=2 / input-csp=1 / input-res=7508x2160 / interlace=0 / total-frames=0 / level-idc=0 / high-tier=1 / uhd-bd=0 / ref=4 / no-allow-non-conformance / no-repeat-headers / annexb / no-aud / no-eob / no-eos / no-hrd / info / hash=0 / temporal-layers=0 / open-gop / min-keyint=23 / keyint=250 / gop-lookahead=0 / bframes=4 / b-adapt=2 / b-pyramid / bframe-bias=0 / rc-lookahead=25 / lookahead-slices=4 / scenecut=40 / no-hist-scenecut / radl=0 / no-splice / no-intra-refresh / ctu=64 / min-cu-size=8 / rect / no-amp / max-tu-size=32 / tu-inter-depth=1 / tu-intra-depth=1 / limit-tu=0 / rdoq-level=2 / dynamic-rd=0.00 / no-ssim-rd / signhide / no-tskip / nr-intra=0 / nr-inter=0 / no-constrained-intra / strong-intra-smoothing / max-merge=3 / limit-refs=3 / limit-modes / me=3 / subme=3 / merange=57 / temporal-mvp / no-frame-dup / no-hme / weightp / no-weightb / no-analyze-src-pics / deblock=0:0 / sao / no-sao-non-deblock / rd=4 / selective-sao=4 / no-early-skip / rskip / no-fast-intra / no-tskip-fast / no-cu-lossless / no-b-intra / no-splitrd-skip / rdpenalty=0 / psy-rd=2.00 / psy-rdoq=1.00 / no-rd-refine / no-lossless / cbqpoffs=0 / crqpoffs=0 / rc=crf / crf=10.0 / qcomp=0.60 / qpstep=4 / stats-write=0 / stats-read=0 / vbv-maxrate=169523 / vbv-bufsize=339046 / vbv-init=0.8 / min-vbv-fullness=50.0 / max-vbv-fullness=80.0 / crf-max=0.0 / crf-min=0.0 / ipratio=1.40 / pbratio=1.30 / aq-mode=2 / aq-strength=1.00 / cutree / zone-count=0 / no-strict-cbr / qg-size=32 / no-rc-grain / qpmax=69 / qpmin=0 / no-const-vbv / sar=1 / overscan=0 / videoformat=5 / range=0 / colorprim=2 / transfer=2 / colormatrix=2 / chromaloc=0 / display-window=0 / cll=0,0 / min-luma=0 / max-luma=255 / log2-max-poc-lsb=8 / vui-timing-info / vui-hrd-info / slices=1 / no-opt-qp-pps / no-opt-ref-list-length-pps / no-multi-pass-opt-rps / scenecut-bias=0.05 / no-opt-cu-delta-qp / no-aq-motion / no-hdr10 / no-hdr10-opt / no-dhdr10-opt / no-idr-recovery-sei / analysis-reuse-level=0 / analysis-save-reuse-level=0 / analysis-load-reuse-level=0 / scale-factor=0 / refine-intra=0 / refine-inter=0 / refine-mv=1 / refine-ctu-distortion=0 / no-limit-sao / ctu-info=0 / no-lowpass-dct / refine-analysis-type=0 / copy-pic=1 / max-ausize-factor=1.0 / no-dynamic-refine / no-single-sei / no-hevc-aq / no-svt / no-field / qp-adaptation-range=1.00 / scenecut-aware-qp=0conformance-window-offsets / right=0 / bottom=0 / decoder-max-rate=0 / no-vbv-live-multi-pass / no-mcstf / no-sbrc
Default : No
Forced : No
Color range : Limited
Audio
ID : 2
Format : E-AC-3 JOC
Format/Info : Enhanced AC-3 with Joint Object Coding
Commercial name : Dolby Digital Plus with Dolby Atmos
Codec ID : A_EAC3
Duration : 1 min 3 s
Bit rate mode : Constant
Bit rate : 768 kb/s
Channel(s) : 6 channels
Channel layout : L R C LFE Ls Rs
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 SPF)
Bit depth : 32 bits
Compression mode : Lossy
Delay relative to video : -58 ms
Stream size : 711 MiB (55%)
Title : VFF
Language : French
Service kind : Complete Main
Default : Yes
Forced : No
Complexity index : 16
Number of dynamic objects : 15
Bed channel count : 1 channel
Bed channel configuration : LFE
Dialog Normalization : -24 dB
compr : -0.28 dB
Dialogue normalization, average : -24 dB
Dialogue normalization, minimum : -24 dB
Dialogue normalization, maximum : -24 dB
Text
ID : 3
Format : UTF-8
Codec ID : S_TEXT/UTF8
Codec ID/Info : UTF-8 Plain Text
Bit rate : 2 b/s
Count of elements : 62
Stream size : 2.13 KiB (0%)
Title : VFF Forced
Language : French
Default : Yes
Forced : Yes
So, there is one issue I need help with. May not be related to this build, but LE in general. I just leave my PC on, but when I come back the next day, the UI is dim, which is expected (maybe auto partial sleep or hibernate after some time). But, starting to re-use it, navigate around doesn't get it out of that dim mode to normal...
...unless I reboot...
How to fix?