Iris Shaders & Satin API Crash: Unrecognized RenderLayer Implementation (IrisRenderLayerWrapper)

What the log looks like

java\.lang\.IllegalArgumentException: Unrecognized RenderLayer implementation class net\.coderbot\.iris\.layer\.IrisRenderLayerWrapper
IrisRenderLayerWrapper\. Layer duplication is only applicable to the default \(MultiPhase\) implementation

How to fix it

1. Update Iris Shaders (along with Sodium) to the latest release available for your Minecraft version, as newer Iris builds resolved this wrapper incompatibility.
2. Update the mod mentioned below Satin in your stack trace (such as Requiem) to its newest compatible release so you get its updated rendering code.
3. Download the latest standalone Satin API mod JAR for your exact Minecraft version and place it in your mods folder; Fabric Loader will use the newer standalone version instead of the outdated copy bundled inside Requiem or other mods.
4. If you are playing a locked modpack and cannot change mods, press K in-game to disable Iris shaders before triggering the visual effect (such as dying or possessing an undead mob in Requiem), or remove Iris Shaders.

Check your own log