diff -U3 /tmp/cirrus-ci-build/src/test/regress/expected/for_portion_of.out /tmp/cirrus-ci-build/build/testrun/regress/regress/results/for_portion_of.out
--- /tmp/cirrus-ci-build/src/test/regress/expected/for_portion_of.out	2026-04-05 05:06:38.578931000 +0000
+++ /tmp/cirrus-ci-build/build/testrun/regress/regress/results/for_portion_of.out	2026-04-05 05:08:44.876676000 +0000
@@ -1099,8 +1099,6 @@
   FOR PORTION OF valid_at FROM '2000-01-01' TO '2001-01-11'
   SET name = 'one^3'
   WHERE id = 1;
-ERROR:  new row for relation "for_portion_of_test2" violates check constraint "fpo2_check"
-DETAIL:  Failing row contains (1, [2000-01-01,2001-01-11), one^3).
 ALTER TABLE for_portion_of_test2 DROP CONSTRAINT fpo2_check;
 -- test inserts violating CHECK constraints
 ALTER TABLE for_portion_of_test2
@@ -1115,12 +1113,13 @@
 SELECT * FROM for_portion_of_test2 WHERE id = 1 ORDER BY valid_at;
  id |        valid_at         | name  
 ----+-------------------------+-------
-  1 | [2000-01-01,2010-01-01) | one
+  1 | [2000-01-01,2001-01-11) | one^3
+  1 | [2001-01-11,2010-01-01) | one
   1 | [2010-01-01,2010-01-05) | one^1
   1 | [2010-01-05,2010-01-07) | one
   1 | [2010-01-07,2010-01-09) | one^2
   1 | [2010-01-09,2020-01-01) | one
-(5 rows)
+(6 rows)
 
 -- DELETE works:
 DELETE FROM for_portion_of_test2
@@ -1222,8 +1221,6 @@
   FOR PORTION OF valid_at ('{[2000-01-01,2001-01-11)}')
   SET name = 'one^3'
   WHERE id = 1;
-ERROR:  new row for relation "for_portion_of_test2" violates check constraint "fpo2_check"
-DETAIL:  Failing row contains (1, {[2000-01-01,2001-01-11)}, one^3).
 ALTER TABLE for_portion_of_test2 DROP CONSTRAINT fpo2_check;
 -- test inserts violating CHECK constraints
 ALTER TABLE for_portion_of_test2
@@ -1233,14 +1230,15 @@
   SET name = 'one^3'
   WHERE id = 1;
 ERROR:  new row for relation "for_portion_of_test2" violates check constraint "fpo2_check"
-DETAIL:  Failing row contains (1, {[2000-01-01,2001-01-01),[2002-02-02,2010-01-07),[2010-01-09,202..., one).
+DETAIL:  Failing row contains (1, {[2002-02-02,2010-01-07),[2010-01-09,2020-01-01)}, one).
 ALTER TABLE for_portion_of_test2 DROP CONSTRAINT fpo2_check;
 SELECT * FROM for_portion_of_test2 WHERE id = 1 ORDER BY valid_at;
  id |                     valid_at                      | name  
 ----+---------------------------------------------------+-------
-  1 | {[2000-01-01,2010-01-07),[2010-01-09,2020-01-01)} | one
+  1 | {[2000-01-01,2001-01-11)}                         | one^3
+  1 | {[2001-01-11,2010-01-07),[2010-01-09,2020-01-01)} | one
   1 | {[2010-01-07,2010-01-09)}                         | one^2
-(2 rows)
+(3 rows)
 
 -- DELETE works:
 DELETE FROM for_portion_of_test2