diff --git a/rfctime/rfc3339.go b/rfctime/rfc3339.go
index 0e350ff..aea8e4f 100644
--- a/rfctime/rfc3339.go
+++ b/rfctime/rfc3339.go
@@ -67,7 +67,7 @@ func (t *RFC3339Time) UnmarshalText(data []byte) error {
 
 func (t *RFC3339Time) UnmarshalBSONValue(bt bsontype.Type, data []byte) error {
 	if bt == bsontype.Null {
-		*t = RFC3339Time{}
+		//t = nil
 		return nil
 	}
 	if bt != bsontype.DateTime {
diff --git a/rfctime/rfc3339Nano.go b/rfctime/rfc3339Nano.go
index 8383b32..b6bef36 100644
--- a/rfctime/rfc3339Nano.go
+++ b/rfctime/rfc3339Nano.go
@@ -67,7 +67,7 @@ func (t *RFC3339NanoTime) UnmarshalText(data []byte) error {
 
 func (t *RFC3339NanoTime) UnmarshalBSONValue(bt bsontype.Type, data []byte) error {
 	if bt == bsontype.Null {
-		*t = RFC3339NanoTime{}
+		//t = nil
 		return nil
 	}
 	if bt != bsontype.DateTime {