diff --git a/pkg/resmgr/cache/container.go b/pkg/resmgr/cache/container.go
index 125e81421..306492883 100644
--- a/pkg/resmgr/cache/container.go
+++ b/pkg/resmgr/cache/container.go
@@ -1027,7 +1027,7 @@ func (c *container) EvalKey(key string) interface{} {
 	case resmgr.KeyNamespace:
 		return c.GetNamespace()
 	case resmgr.KeyQOSClass:
-		return c.GetQOSClass()
+		return string(c.GetQOSClass())
 	case resmgr.KeyLabels:
 		return c.Ctr.GetLabels()
 	case resmgr.KeyTags: