diff --git a/contrib/test_decoding/Makefile b/contrib/test_decoding/Makefile
index 02e961f4d31..2f8545eff8c 100644
--- a/contrib/test_decoding/Makefile
+++ b/contrib/test_decoding/Makefile
@@ -6,9 +6,15 @@ PGFILEDESC = "test_decoding - example of a logical decoding output plugin"
 REGRESS = ddl xact rewrite toast permissions decoding_in_xact \
 	decoding_into_rel binary prepared replorigin time messages \
 	spill slot truncate stream stats twophase twophase_stream
+
+# slot_creation_error terminates another backend, whose FATAL message can be
+# lost on Windows, making the test unstable there.
+# See https://postgr.es/m/088AB35D-0860-494A-A9CF-8B301543AA51@yandex-team.ru
+SLOT_CREATION_TST = $(if $(filter win32,$(PORTNAME)),,slot_creation_error)
+
 ISOLATION = mxact delayed_startup ondisk_startup concurrent_ddl_dml \
 	oldest_xmin snapshot_transfer subxact_without_top concurrent_stream \
-	twophase_snapshot slot_creation_error catalog_change_snapshot \
+	twophase_snapshot $(SLOT_CREATION_TST) catalog_change_snapshot \
 	skip_snapshot_restore invalidation_distribution
 
 REGRESS_OPTS = --temp-config $(top_srcdir)/contrib/test_decoding/logical.conf
diff --git a/contrib/test_decoding/meson.build b/contrib/test_decoding/meson.build
index 03dd80b7f19..94498b5728c 100644
--- a/contrib/test_decoding/meson.build
+++ b/contrib/test_decoding/meson.build
@@ -16,6 +16,28 @@ test_decoding = shared_module('test_decoding',
 )
 contrib_targets += test_decoding
 
+test_decoding_isolation = [
+  'mxact',
+  'delayed_startup',
+  'ondisk_startup',
+  'catalog_change_snapshot',
+  'concurrent_ddl_dml',
+  'oldest_xmin',
+  'snapshot_transfer',
+  'subxact_without_top',
+  'concurrent_stream',
+  'twophase_snapshot',
+  'skip_snapshot_restore',
+  'invalidation_distribution',
+]
+
+# slot_creation_error terminates another backend, whose FATAL message can be
+# lost on Windows, making the test unstable there.
+# See https://postgr.es/m/088AB35D-0860-494A-A9CF-8B301543AA51@yandex-team.ru
+if host_system != 'windows'
+  test_decoding_isolation += 'slot_creation_error'
+endif
+
 tests += {
   'name': 'test_decoding',
   'sd': meson.current_source_dir(),
@@ -50,21 +72,7 @@ tests += {
     'runningcheck': false,
   },
   'isolation': {
-    'specs': [
-      'mxact',
-      'delayed_startup',
-      'ondisk_startup',
-      'catalog_change_snapshot',
-      'concurrent_ddl_dml',
-      'oldest_xmin',
-      'snapshot_transfer',
-      'subxact_without_top',
-      'concurrent_stream',
-      'twophase_snapshot',
-      'slot_creation_error',
-      'skip_snapshot_restore',
-      'invalidation_distribution',
-    ],
+    'specs': test_decoding_isolation,
     'regress_args': [
       '--temp-config', files('logical.conf'),
     ],
diff --git a/src/test/modules/injection_points/Makefile b/src/test/modules/injection_points/Makefile
index 5b96110209a..146abde638d 100644
--- a/src/test/modules/injection_points/Makefile
+++ b/src/test/modules/injection_points/Makefile
@@ -12,10 +12,15 @@ PGFILEDESC = "injection_points - facility for injection points"
 REGRESS = injection_points reindex_conc vacuum
 REGRESS_OPTS = --dlpath=$(top_builddir)/src/test/regress
 
+# wait_cleanup terminates another backend, whose FATAL message can be lost
+# on Windows, making the test unstable there.
+# See https://postgr.es/m/088AB35D-0860-494A-A9CF-8B301543AA51@yandex-team.ru
+WAIT_CLEANUP_TST = $(if $(filter win32,$(PORTNAME)),,wait_cleanup)
+
 ISOLATION = inplace \
 	    reindex_concurrently_deferred \
 	    syscache-update-pruned \
-	    wait_cleanup \
+	    $(WAIT_CLEANUP_TST) \
 	    heap_lock_update \
 	    on_conflict_probe_window
 
diff --git a/src/test/modules/injection_points/meson.build b/src/test/modules/injection_points/meson.build
index 425a465b3d3..8892536c35c 100644
--- a/src/test/modules/injection_points/meson.build
+++ b/src/test/modules/injection_points/meson.build
@@ -26,6 +26,21 @@ test_install_data += files(
   'injection_points--1.0.sql',
 )
 
+injection_points_isolation = [
+  'inplace',
+  'reindex_concurrently_deferred',
+  'syscache-update-pruned',
+  'heap_lock_update',
+  'on_conflict_probe_window',
+]
+
+# wait_cleanup terminates another backend, whose FATAL message can be lost
+# on Windows, making the test unstable there.
+# See https://postgr.es/m/088AB35D-0860-494A-A9CF-8B301543AA51@yandex-team.ru
+if host_system != 'windows'
+  injection_points_isolation += 'wait_cleanup'
+endif
+
 tests += {
   'name': 'injection_points',
   'sd': meson.current_source_dir(),
@@ -41,14 +56,7 @@ tests += {
     'runningcheck': false,
   },
   'isolation': {
-    'specs': [
-      'inplace',
-      'reindex_concurrently_deferred',
-      'syscache-update-pruned',
-      'wait_cleanup',
-      'heap_lock_update',
-      'on_conflict_probe_window',
-    ],
+    'specs': injection_points_isolation,
     'runningcheck': false, # see syscache-update-pruned
   },
 }