diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c
index 6649e7b7feb..3020a628443 100644
--- a/src/backend/utils/adt/jsonfuncs.c
+++ b/src/backend/utils/adt/jsonfuncs.c
@@ -4548,9 +4548,11 @@ jsonb_set_lax(PG_FUNCTION_ARGS)
 
 		newval = DirectFunctionCall1(jsonb_in, CStringGetDatum("null"));
 
-		fcinfo->args[2].value = newval;
-		fcinfo->args[2].isnull = false;
-		return jsonb_set(fcinfo);
+		return DirectFunctionCall4(jsonb_set,
+								   PG_GETARG_DATUM(0),
+								   PG_GETARG_DATUM(1),
+								   newval,
+								   PG_GETARG_DATUM(3));
 	}
 	else if (strcmp(handle_val, "delete_key") == 0)
 	{
diff --git a/src/test/regress/expected/jsonb.out b/src/test/regress/expected/jsonb.out
index 42c0d69c6e9..15b18f06c95 100644
--- a/src/test/regress/expected/jsonb.out
+++ b/src/test/regress/expected/jsonb.out
@@ -4674,6 +4674,34 @@ select jsonb_set_lax('{"a":1,"b":2}', '{b}', null, null_value_treatment => 'use_
  {"a": 1, "b": null}
 (1 row)
 
+-- multi-row cases with a constant NULL new_value
+select jsonb_set_lax(j, '{a}', null, true, t)
+from (values ('{"a":1}'::jsonb, 'use_json_null'),
+             ('{"a":1}'::jsonb, 'delete_key')) v(j, t);
+ jsonb_set_lax 
+---------------
+ {"a": null}
+ {}
+(2 rows)
+
+select jsonb_set_lax(j, '{a}', null, true, t)
+from (values ('{"a":1}'::jsonb, 'use_json_null'),
+             ('{"a":1}'::jsonb, 'return_target')) v(j, t);
+ jsonb_set_lax 
+---------------
+ {"a": null}
+ {"a": 1}
+(2 rows)
+
+select jsonb_set_lax(j, '{a}', null)
+from (values ('{"a":1}'::jsonb), ('{"a":2}'::jsonb), ('{"a":3}'::jsonb)) v(j);
+ jsonb_set_lax 
+---------------
+ {"a": null}
+ {"a": null}
+ {"a": null}
+(3 rows)
+
 \pset null ''
 -- jsonb_insert
 select jsonb_insert('{"a": [0,1,2]}', '{a, 1}', '"new_value"');
diff --git a/src/test/regress/sql/jsonb.sql b/src/test/regress/sql/jsonb.sql
index e47f0796457..9b56c33b1ec 100644
--- a/src/test/regress/sql/jsonb.sql
+++ b/src/test/regress/sql/jsonb.sql
@@ -1212,6 +1212,16 @@ select jsonb_set_lax('{"a":1,"b":2}', '{b}', null, null_value_treatment => 'retu
 select jsonb_set_lax('{"a":1,"b":2}', '{b}', null, null_value_treatment => 'delete_key') as delete_key;
 select jsonb_set_lax('{"a":1,"b":2}', '{b}', null, null_value_treatment => 'use_json_null') as use_json_null;
 
+-- multi-row cases with a constant NULL new_value
+select jsonb_set_lax(j, '{a}', null, true, t)
+from (values ('{"a":1}'::jsonb, 'use_json_null'),
+             ('{"a":1}'::jsonb, 'delete_key')) v(j, t);
+select jsonb_set_lax(j, '{a}', null, true, t)
+from (values ('{"a":1}'::jsonb, 'use_json_null'),
+             ('{"a":1}'::jsonb, 'return_target')) v(j, t);
+select jsonb_set_lax(j, '{a}', null)
+from (values ('{"a":1}'::jsonb), ('{"a":2}'::jsonb), ('{"a":3}'::jsonb)) v(j);
+
 \pset null ''
 
 -- jsonb_insert