diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
index 136e2023ba..a43ba35dda 100644
--- a/src/Analyser/MutatingScope.php
+++ b/src/Analyser/MutatingScope.php
@@ -3603,6 +3603,15 @@ private function createConditionalExpressions(
 			}
 
 			foreach ($variableTypeGuards as $guardExprString => $guardHolder) {
+				if (
+					array_key_exists($exprString, $theirExpressionTypes)
+					&& $theirExpressionTypes[$exprString]->getCertainty()->yes()
+					&& array_key_exists($guardExprString, $theirExpressionTypes)
+					&& $theirExpressionTypes[$guardExprString]->getCertainty()->yes()
+					&& !$guardHolder->getType()->isSuperTypeOf($theirExpressionTypes[$guardExprString]->getType())->no()
+				) {
+					continue;
+				}
 				$conditionalExpression = new ConditionalExpressionHolder([$guardExprString => $guardHolder], $holder);
 				$conditionalExpressions[$exprString][$conditionalExpression->getKey()] = $conditionalExpression;
 			}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-10085.php b/tests/PHPStan/Analyser/nsrt/bug-10085.php
new file mode 100644
index 0000000000..aa8dcc3b8a
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-10085.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Bug10085;
+
+use function PHPStan\Testing\assertType;
+
+class HelloWorld
+{
+	/**
+	 * @param array<int, string> $foo
+	 * @param list<string> $bar
+	 */
+	public function sayHello(array $foo, array $bar): void
+	{
+		$a = $foo;
+		if ($a === []) {
+			$a = $bar;
+		}
+
+		if ($a === []) {
+			return;
+		}
+
+		assertType('array<int, string>', $foo);
+	}
+}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-11328.php b/tests/PHPStan/Analyser/nsrt/bug-11328.php
new file mode 100644
index 0000000000..bf315fc73c
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-11328.php
@@ -0,0 +1,27 @@
+<?php // lint >= 8.1
+
+declare(strict_types = 1);
+
+namespace Bug11328;
+
+use function PHPStan\Testing\assertType;
+
+enum Status: string {
+	case Live = 's1';
+	case Expired = 's2';
+}
+
+/** @param Status[] $statuses */
+function check(array $statuses): void {
+	$fromDeadline = null;
+	$toDeadline = null;
+	if (in_array(Status::Live, $statuses, true)) {
+		$fromDeadline = (new \DateTimeImmutable())->setTime(23, 59, 59);
+	}
+	if (in_array(Status::Expired, $statuses, true)) {
+		assertType('DateTimeImmutable|null', $fromDeadline);
+		if ($fromDeadline === null) {
+			$toDeadline = (new \DateTimeImmutable())->setTime(0, 0, 0);
+		}
+	}
+}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-14211.php b/tests/PHPStan/Analyser/nsrt/bug-14211.php
new file mode 100644
index 0000000000..b3ef9d987c
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-14211.php
@@ -0,0 +1,27 @@
+<?php // lint >= 8.0
+
+declare(strict_types = 1);
+
+namespace Bug14211;
+
+use function PHPStan\Testing\assertType;
+
+/** @param array<mixed> $data */
+function DoSomithing(array $data): bool {
+
+	if (!isset($data['x']))
+		return false;
+
+	$m = isset($data['y']);
+
+	if ($m) {
+		assertType('true', $m); // ok: true
+	}
+	assertType('bool', $m); // ok: bool
+
+	if ($m) {
+		assertType('true', $m); // <-- should not be: NEVER
+	}
+
+	return true;
+}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-14411-regression.php b/tests/PHPStan/Analyser/nsrt/bug-14411-regression.php
new file mode 100644
index 0000000000..31fb5421b0
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-14411-regression.php
@@ -0,0 +1,36 @@
+<?php // lint >= 8.0
+
+declare(strict_types = 1);
+
+namespace Bug14411Regression;
+
+use function PHPStan\Testing\assertType;
+use function PHPStan\Testing\assertVariableCertainty;
+use PHPStan\TrinaryLogic;
+
+interface OrderInterface {}
+
+class Event
+{
+	/** @return mixed */
+	public function getSubject()
+	{
+		return new \stdClass();
+	}
+}
+
+function getOrder(Event|OrderInterface $event): OrderInterface
+{
+	if ($event instanceof Event) {
+		$order = $event->getSubject();
+		assert($order instanceof OrderInterface);
+	}
+
+	if ($event instanceof OrderInterface) {
+		$order = $event;
+	}
+
+	assertVariableCertainty(TrinaryLogic::createYes(), $order);
+
+	return $order;
+}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-14411.php b/tests/PHPStan/Analyser/nsrt/bug-14411.php
new file mode 100644
index 0000000000..753532ed59
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-14411.php
@@ -0,0 +1,34 @@
+<?php // lint >= 8.0
+
+declare(strict_types = 1);
+
+namespace Bug14411;
+
+use function PHPStan\Testing\assertType;
+
+/** @phpstan-impure */
+function get_mixed(): mixed {
+	return random_int(0, 1) ? 'foo' : null;
+}
+
+/** @phpstan-impure */
+function get_optional_int(): ?int {
+	return random_int(0, 1) ? 42 : null;
+}
+
+function (): void {
+	$a = get_mixed();
+
+	if ($a !== null) {
+		$b = $a;
+	}
+	else {
+		$b = get_optional_int();
+	}
+	if ($b !== null) {
+		assertType('mixed', $a);
+		if ($a === null) {
+			echo 'this is absolutely possible';
+		}
+	}
+};