diff --git a/tests/bugs/core_4321_test.py b/tests/bugs/core_4321_test.py
index af43f41a..60e2c660 100644
--- a/tests/bugs/core_4321_test.py
+++ b/tests/bugs/core_4321_test.py
@@ -6,7 +6,12 @@ ISSUE:       4644
 TITLE:       Regression: ISQL does not destroy the SQL statement
 DESCRIPTION:
 JIRA:        CORE-4321
-FBTEST:      bugs.core_4321
+NOTES:
+    [31.12.2024] pzotov
+    Added forgotten semicolon after 'SET LIST ON'.
+    Parsing problem appeared on 6.0.0.0.570 after d6ad19aa07deeaac8107a25a9243c5699a3c4ea1
+    ("Refactor ISQL creating FrontendParser class").
+    It looks weird how it could work w/o 'token unknown / list' all this time in all major FB versions :-)
 """
 
 import pytest
@@ -16,54 +21,55 @@ db = db_factory()
 
 test_script = """
     -- NB: 2.1.7 FAILED, output contains '4' for select count(*) ...
-    set list on
-    select 1 x from rdb$database;
-    select 1 x from rdb$database;
-    select 1 x from rdb$database;
-    select 1 x from rdb$database;
+    set list on;
+    select /* tag_for_watch */ 1 point_a from rdb$database;
+    select /* tag_for_watch */ 1 point_a from rdb$database;
+    select /* tag_for_watch */ 1 point_a from rdb$database;
+    select /* tag_for_watch */ 1 point_a from rdb$database;
 
-    select count(*) c from mon$statements s
-    where s.mon$sql_text containing 'select 1 x' -- 08-may-2017: need for 4.0 Classic! Currently there is also query with RDB$AUTH_MAPPING data in mon$statements
+    select count(*) count_after_point_a from mon$statements s
+    where s.mon$sql_text containing '/* tag_for_watch */'
     ;
     commit;
-    select count(*) c from mon$statements s
-    where s.mon$sql_text containing 'select 1 x'
+    select count(*) count_after_commit_a from mon$statements s
+    where s.mon$sql_text containing '/* tag_for_watch */'
     ;
 
-    select 1 x from rdb$database;
-    select 1 x from rdb$database;
-    select 1 x from rdb$database;
-    select 1 x from rdb$database;
+    select /* tag_for_watch */ 1 point_b from rdb$database;
+    select /* tag_for_watch */ 1 point_b from rdb$database;
+    select /* tag_for_watch */ 1 point_b from rdb$database;
+    select /* tag_for_watch */ 1 point_b from rdb$database;
 
-    select count(*) c from mon$statements s
-    where s.mon$sql_text containing 'select 1 x'
+    select count(*) count_after_point_b from mon$statements s
+    where s.mon$sql_text containing '/* tag_for_watch */'
     ;
     commit;
 
-    select count(*) c from mon$statements s
-    where s.mon$sql_text containing 'select 1 x'
+    select count(*) count_after_commit_b from mon$statements s
+    where s.mon$sql_text containing '/* tag_for_watch */'
     ;
 """
 
-act = isql_act('db', test_script)
+act = isql_act('db', test_script,  substitutions=[('[ \t]+', ' ')] )
 
 expected_stdout = """
-    X                               1
-    X                               1
-    X                               1
-    C                               1
-    C                               1
-    X                               1
-    X                               1
-    X                               1
-    X                               1
-    C                               1
-    C                               1
+    POINT_A 1
+    POINT_A 1
+    POINT_A 1
+    POINT_A 1
+    COUNT_AFTER_POINT_A 1
+    COUNT_AFTER_COMMIT_A 1
+    POINT_B 1
+    POINT_B 1
+    POINT_B 1
+    POINT_B 1
+    COUNT_AFTER_POINT_B 1
+    COUNT_AFTER_COMMIT_B 1
 """
 
 @pytest.mark.version('>=3')
 def test_1(act: Action):
     act.expected_stdout = expected_stdout
-    act.execute()
+    act.execute(combine_output = True)
     assert act.clean_stdout == act.clean_expected_stdout