diff --git a/pkg/truncindex/truncindex.go b/pkg/truncindex/truncindex.go
index d5c840cf13..b7a11a38c0 100644
--- a/pkg/truncindex/truncindex.go
+++ b/pkg/truncindex/truncindex.go
@@ -108,7 +108,7 @@ func (idx *TruncIndex) Get(s string) (string, error) {
 		if id != "" {
 			// we haven't found the ID if there are two or more IDs
 			id = ""
-			return ErrAmbiguousPrefix{prefix: string(prefix)}
+			return ErrAmbiguousPrefix{prefix: s}
 		}
 		id = string(prefix)
 		return nil