Theme Broken on startup - Entirely changed around without rollback

Type: Bug

Steps to Reproduce:

1. Start vscode
2. Theme is entirely different with no other updates applied. Nothing in release notes.

The entire theme is changed to something which has no useful contrasts, visual cues, etc. Harder to use, no notice, no rollback present.

VS Code version: Code 1.131.0 (e4c7e7b1d6d060162f4aa7f8225271b67ce1df75, 2026-07-28T10:51:25Z)
OS version: Windows_NT x64 10.0.26200
Modes:
Remote OS version: Linux x64 6.5.0-45-generic

System Info

|Item|Value|
|---|---|
|CPUs|13th Gen Intel(R) Core(TM) i7-13700 (24 x 2112)|
|GPU Status|2d_canvas: enabled
GPU0: VENDOR= 0x10de, DEVICE=0x1ff2 [NVIDIA T400 4GB], DRIVER_VENDOR=NVIDIA, DRIVER_VERSION=32.0.15.8142 *ACTIVE*
GPU1: VENDOR= 0x8086, DEVICE=0xa780 [Intel(R) UHD Graphics 770], DRIVER_VERSION=32.0.101.7079
GPU2: VENDOR= 0x1414, DEVICE=0x008c [Microsoft Basic Render Driver], DRIVER_VERSION=10.0.26100.8875
Machine model name:
Machine model version:
direct_rendering_display_compositor: disabled_off_ok
gpu_compositing: enabled
multiple_raster_threads: enabled_on
opengl: enabled_on
rasterization: enabled
raw_draw: disabled_off_ok
skia_graphite: disabled_off
trees_in_viz: disabled_off
video_decode: enabled
video_encode: enabled
webgl: enabled
webgpu: enabled
webnn: disabled_off|
|Load (avg)|undefined|
|Memory (System)|127.64GB (95.86GB free)|
|Process Argv|--disable-extensions --crash-reporter-id 5e804922-86d8-44bc-81dd-951a6493cd46|
|Screen Reader|no|
|VM|27%|

|Item|Value|
|---|---|
|Remote|SSH: ubuntu2204|
|OS|Linux x64 6.5.0-45-generic|
|CPUs|13th Gen Intel(R) Core(TM) i7-13700 (16 x 0)|
|Memory (System)|62.75GB (61.28GB free)|
|VM|100%|
Extensions disabled
A/B Experiments

```
vsliv368cf:30146710
binariesv615:30325510
nativeloc1:31344060
dwcopilot:31170013
dwoutputs:31242946
copilot_t_ci:31333650
e5gg6876:31282496
pythonrdcb7:31342333
6518g693:31463988
aj953862:31281341
82j33506:31327384
envsactivate1:31551504
cloudbuttont:31379625
3efgi100_wstrepl:31403338
56b7f661:31457055
ec5jj548:31422691
cp_cls_t_966_ss:31526232
4je02754:31466945
8hhj4413:31478653
cp_cls_t_1081:31454832
conptydll_true:31498968
e9c30283:31461165
test_treatment2:31471001
46204921:31447328
idci7584:31464702
e3e4d672:31494082
ei9d7968:31496641
chat:31457767
7e187181:31503455
ghj88844:31499326
23c7c724:31520045
ddid_t:31478206
hmra_i5g22:31518061
7df3h592:31512476
cp_cls_t_1082:31535311
logging_enabled_new:31498466
j0d79568:31499440
jb_cp_cls_t_632:31543129
56dj4588:31512888
32d76977:31512328
ha629193:31508444
cdk-lw-on:31524445
f9bf7985:31543584
jh5f2457_c:31540921
hgf2d445:31529595
8hfba999:31537718
jbcp_cls_pctr_t:31531130
61138546:31518536
cp_intellij_t_nes:31548657
d7b18187:31526828
ahp-both-windows:31556933
h561g132:31533256
sessions_3:31532893
ihg5j128:31534457
f412h606:31551416
9gg7f176:31542112
5fe6f778:31554331
allow-none:31555437
fd5dc207:31551400
36h42362:31560307
c7c27ce7:31554789
8hc4g144:31558143
1532g621_copy:31554320
treatment-23-1:31555779
unuse_dynamic_mcp:31555281
0d8dfbc3:31560381
switchtoauto:31559321
session-mark-done:31558131

```