Setting Tint on some meshes' faces seems to be impossible with PBR

[jellyfish-linden]

Environment

Second Life Release 26.2.0.25021396775 (64bit)
Release Notes

You are at 101.1, 188.8, 22.9 in Jellyfish Aquarium located at simhost-07e5b72529208ad6c.agni
SLURL: https://maps.secondlife.com/secondlife/Jellyfish%20Aquarium/101/189/23
(global coordinates 239205.0, 245693.0, 22.9)
Luau 2026-04-09.24211153544
Release Notes

CPU: Apple M1 Max (2400 MHz)
Memory: 32768 MB
OS Version: macOS 26.3.1 Darwin 25.3.0 Darwin Kernel Version 25.3.0: Wed Jan 28 20:54:46 PST 2026; root:xnu-12377.91.3~2/RELEASE_ARM64_T6000 arm64
Graphics Card Vendor: Apple
Graphics Card: Apple M1 Max

OpenGL Version: 4.1 Metal - 90.5

Window size: 1654x943
Font Size Adjustment: 96pt
UI Scaling: 1
Draw distance: 128m
Bandwidth: 3000kbit/s
LOD factor: 1.375
Render quality: 3
Texture memory: 25559MB
Disk cache: Max size 2150.4 MB (62.3% used)
HiDPI display mode:

J2C Decoder Version: KDU v8.4.1
Audio Driver Version: OpenAL, version 1.1 ALSOFT 1.24.2 / OpenAL Community / OpenAL Soft: OpenAL Soft
Dullahan: 1.24.0.202510081737
CEF: 139.0.40+g465474a+chromium-139.0.7258.139
Chromium: 139.0.7258.139
LibVLC Version: 3.0.21
Voice Server Version: Secondlife WebRTC Gateway

Packets Lost: 2/33188 (0.0%)
May 04 2026 14:25:00

Description

When setting some mesh faces' tint value it seems like it bounces back to some default value.

Reproduction steps

This one is a bit clearer with a video, but:

1. Attach one of these meshes. (not sure how many it applies to or which)
2. Right click item -> edit item -> select face
3. Pick face 1
4. Set a material (any material should do)
5. Click "edit selected" next to material
6. Click the tint color
7. Try to change the tint

https://github.com/user-attachments/assets/028210ea-873e-49ea-96cf-b1190bdf93c5

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[canny]

This issue has been linked to a Canny post: PBR issue on some faces of some Mesh items (#5% of items not compatible) 🎉

[jellyfish-linden]

Repro mesh is at https://maps.secondlife.com/secondlife/Danger!%20Danger!/71/82/39

[Dan-Linden]

This reminds me of #1901

[Dan-Linden]

Test:
Apply a material
relog
If the material is missing or changed, it's the same as #1901

[akleshchev]

Material params have only 1 material listed (first face has the material, we are editing the second one). Trying to set or unset material drops the change after a relog (there do not appear to be any problems with face/te/texture count mismatch, just the gltf), trying to change override returns 404. This is not an exact match of 1901, but appears adjusted to #1901.

Server should not be ignoring viewer's attempt to set a material for a valid face. Which fix for #1901 should also cover. I think this needs retesting once #5413 merges and once server side goes live.