EnvoyFilter configuration not applied to proxy

EnvoyFilter resource exists but is not being applied to the Envoy proxy configuration, typically due to incorrect namespace scope, workloadSelector label mismatch, or overly specific match criteria in configPatches

Verify filter name appears in config dump using grep. Check that EnvoyFilter namespace matches target (use istio-system for cluster-wide). Validate workloadSelector labels match target pod labels. Review match criteria specificity in configPatches section.