diff --git a/msgpack_reader.go b/msgpack_reader.go
index a9a0df5..a3afebe 100644
--- a/msgpack_reader.go
+++ b/msgpack_reader.go
@@ -530,6 +530,10 @@ func (rd *msgpackReader) Skip() error {
 }
 
 func (rd *msgpackReader) TryReadMask() (bool, FieldsMask, error) {
+	if rd.curr.assoc {
+		return false, FieldsMask{}, nil
+	}
+
 	maskLen, err := rd.dec.DecodeArrayLen()
 	if err != nil {
 		if err == io.EOF {