diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
index f8219658d15..8cc3329b835 100644
--- a/src/Analyser/MutatingScope.php
+++ b/src/Analyser/MutatingScope.php
@@ -1160,7 +1160,10 @@ public function issetCheck(Expr $expr, callable $typeCallback, ?bool $result = n
 			if ($propertyReflection->hasNativeType() && !$propertyReflection->isVirtual()->yes()) {
 				if (!$this->hasExpressionType($expr)->yes()) {
 					$nativeReflection = $propertyReflection->getNativeReflection();
-					if ($nativeReflection === null || !$nativeReflection->isPromoted() || (!$nativeReflection->isReadOnly() && !$nativeReflection->isHooked())) {
+					if (
+						($nativeReflection === null || !$nativeReflection->getNativeReflection()->hasDefaultValue())
+						&& ($nativeReflection === null || !$nativeReflection->isPromoted() || (!$nativeReflection->isReadOnly() && !$nativeReflection->isHooked()))
+					) {
 						if ($expr instanceof Node\Expr\PropertyFetch) {
 							return $this->issetCheckUndefined($expr->var);
 						}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-10786.php b/tests/PHPStan/Analyser/nsrt/bug-10786.php
new file mode 100644
index 00000000000..4dc9333aba6
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-10786.php
@@ -0,0 +1,23 @@
+<?php declare(strict_types = 1);
+
+namespace Bug10786;
+
+use function PHPStan\Testing\assertType;
+
+class Value {
+	public ?int	$value = null;
+}
+
+class HelloWorld
+{
+	public function sayHello(Value $a, Value $b): int
+	{
+		if (is_null($a->value) && is_null($b->value)) {
+			throw new \Exception();
+		}
+
+		assertType('int', $a->value ?? $b->value);
+
+		return $a->value ?? $b->value;
+	}
+}
diff --git a/tests/PHPStan/Analyser/nsrt/isset-coalesce-empty-type.php b/tests/PHPStan/Analyser/nsrt/isset-coalesce-empty-type.php
index ad81a1e6ac1..caa54683c96 100644
--- a/tests/PHPStan/Analyser/nsrt/isset-coalesce-empty-type.php
+++ b/tests/PHPStan/Analyser/nsrt/isset-coalesce-empty-type.php
@@ -246,7 +246,7 @@ class FooNativeProp
 	public int $canBeUninitialized;
 
 	function doFoo(FooNativeProp $foo): void {
-		assertType('bool', isset($foo->hasDefaultValue));
+		assertType('true', isset($foo->hasDefaultValue));
 
 		$foo->isAssignedBefore = 5;
 		assertType('true', isset($foo->isAssignedBefore));
diff --git a/tests/PHPStan/Analyser/nsrt/isset-property-default-value.php b/tests/PHPStan/Analyser/nsrt/isset-property-default-value.php
new file mode 100644
index 00000000000..0fc19bb8f6e
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/isset-property-default-value.php
@@ -0,0 +1,32 @@
+<?php declare(strict_types = 1);
+
+namespace IssetPropertyDefaultValue;
+
+use function PHPStan\Testing\assertType;
+
+class Holder
+{
+
+	public ?int $value = null;
+
+	public ?int $noDefault;
+
+}
+
+function coalesceWithDefault(Holder $a, Holder $b): void
+{
+	if ($a->value === null && $b->value === null) {
+		throw new \LogicException();
+	}
+
+	assertType('int', $a->value ?? $b->value);
+}
+
+function coalesceWithoutDefault(Holder $a, Holder $b): void
+{
+	if ($a->noDefault === null && $b->noDefault === null) {
+		throw new \LogicException();
+	}
+
+	assertType('int|null', $a->noDefault ?? $b->noDefault);
+}