diff --git a/cache/cache.go b/cache/cache.go
index 14ac138c..845c4136 100644
--- a/cache/cache.go
+++ b/cache/cache.go
@@ -17,7 +17,6 @@ limitations under the License.
 package cache
 
 import (
-	"errors"
 	"fmt"
 	"time"
 
@@ -114,7 +113,7 @@ func (c *Cache) service() {
 				val := c.cache[req.key]
 				val.atime = time.Now()
 				resp.existingValue = val.value
-				resp.error = errors.New("value already exists")
+				resp.error = fission.MakeError(fission.ErrorNameExists, "key already exists")
 			} else {
 				c.cache[req.key] = &Value{
 					value: req.value,
diff --git a/poolmgr/functionServiceCache.go b/poolmgr/functionServiceCache.go
index 25225298..a1fb5ea2 100644
--- a/poolmgr/functionServiceCache.go
+++ b/poolmgr/functionServiceCache.go
@@ -22,6 +22,7 @@ import (
 
 	"k8s.io/client-go/1.5/pkg/api"
 
+	"github.com/fission/fission"
 	"github.com/fission/fission/cache"
 	"github.com/fission/fission/tpr"
 )
@@ -134,6 +135,7 @@ func (fsc *functionServiceCache) GetByFunction(m *api.ObjectMeta) (*funcSvc, err
 	return &fsvcCopy, nil
 }
 
+// TODO: error should be second return
 func (fsc *functionServiceCache) Add(fsvc funcSvc) (error, *funcSvc) {
 	err, existing := fsc.byFunction.Set(tpr.CacheKey(fsvc.function), &fsvc)
 	if err != nil {
@@ -152,13 +154,25 @@ func (fsc *functionServiceCache) Add(fsvc funcSvc) (error, *funcSvc) {
 	fsvc.ctime = now
 	fsvc.atime = now
 
+	// Add to byAddress and byPod caches. Ignore NameExists errors
+	// because of multiple-specialization. See issue #331.
 	err, _ = fsc.byAddress.Set(fsvc.address, *fsvc.function)
 	if err != nil {
+		if fe, ok := err.(fission.Error); ok {
+			if fe.Code == fission.ErrorNameExists {
+				err = nil
+			}
+		}
 		log.Printf("error caching fsvc: %v", err)
 		return err, nil
 	}
 	err, _ = fsc.byPod.Set(fsvc.podName, *fsvc.function)
 	if err != nil {
+		if fe, ok := err.(fission.Error); ok {
+			if fe.Code == fission.ErrorNameExists {
+				err = nil
+			}
+		}
 		log.Printf("error caching fsvc: %v", err)
 		return err, nil
 	}
diff --git a/poolmgr/gp.go b/poolmgr/gp.go
index 117e8879..888d2b9a 100644
--- a/poolmgr/gp.go
+++ b/poolmgr/gp.go
@@ -511,13 +511,18 @@ func (gp *GenericPool) GetFuncSvc(m *api.ObjectMeta) (*funcSvc, error) {
 
 	err, existingFsvc := gp.fsCache.Add(*fsvc)
 	if err != nil {
-		// Some other thread beat us to it -- return the other thread's fsvc and clean up
-		// our own.
-		log.Printf("func svc already exists: %v", existingFsvc.podName)
-		go func() {
-			gp.kubernetesClient.Core().Pods(gp.namespace).Delete(fsvc.podName, nil)
-		}()
-		return existingFsvc, nil
+		if fe, ok := err.(fission.Error); ok {
+			if fe.Code == fission.ErrorNameExists {
+				// Some other thread beat us to it -- return the other thread's fsvc and clean up
+				// our own.
+				log.Printf("func svc already exists: %v", existingFsvc.podName)
+				go func() {
+					gp.kubernetesClient.Core().Pods(gp.namespace).Delete(fsvc.podName, nil)
+				}()
+				return existingFsvc, nil
+			}
+		}
+		return nil, err
 	}
 	return fsvc, nil
 }