diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4bb1422da6..00e03a598f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -527,7 +527,7 @@ endif()
 
 # Disable ESSL 1.0 code generation.
 if (NOT FILAMENT_ENABLE_FEATURE_LEVEL_0)
-  set(MATC_API_FLAGS ${MATC_API_FLAGS} -1)
+    set(MATC_API_FLAGS ${MATC_API_FLAGS} -1)
 endif()
 
 # Enable debug info (preserves names in SPIR-V)
diff --git a/libs/filamat/src/GLSLPostProcessor.cpp b/libs/filamat/src/GLSLPostProcessor.cpp
index 817429bb66..b4aaf54e4a 100644
--- a/libs/filamat/src/GLSLPostProcessor.cpp
+++ b/libs/filamat/src/GLSLPostProcessor.cpp
@@ -397,6 +397,8 @@ bool GLSLPostProcessor::process(const std::string& inputShader, Config const& co
         case MaterialBuilder::Optimization::SIZE:
         case MaterialBuilder::Optimization::PERFORMANCE:
             if (config.featureLevel == filament::backend::FeatureLevel::FEATURE_LEVEL_0) {
+                // Full optimization blocked by upstream issue:
+                // https://github.com/KhronosGroup/SPIRV-Cross/issues/2223
                 preprocessOptimization(tShader, config, internalConfig);
             } else {
                 fullOptimization(tShader, config, internalConfig);