diff --git a/src/Analyser/ExprHandler/AssignHandler.php b/src/Analyser/ExprHandler/AssignHandler.php
index df779e633e..b63fccc5de 100644
--- a/src/Analyser/ExprHandler/AssignHandler.php
+++ b/src/Analyser/ExprHandler/AssignHandler.php
@@ -991,13 +991,16 @@ private function produceArrayDimFetchAssignValueToWrite(array $dimFetchStack, ar
 				$offsetType !== null
 				&& $arrayDimFetch !== null
 				&& $scope->hasExpressionType($arrayDimFetch)->yes()
-				&& !$offsetValueType->hasOffsetValueType($offsetType)->no()
 			) {
 				$hasOffsetType = null;
-				if ($offsetType instanceof ConstantStringType || $offsetType instanceof ConstantIntegerType) {
-					$hasOffsetType = new HasOffsetValueType($offsetType, $valueToWrite);
+				if ($offsetValueType->hasOffsetValueType($offsetType)->no()) {
+					$valueToWrite = $offsetValueType->setOffsetValueType($offsetType, $valueToWrite);
+				} else {
+					if ($offsetType instanceof ConstantStringType || $offsetType instanceof ConstantIntegerType) {
+						$hasOffsetType = new HasOffsetValueType($offsetType, $valueToWrite);
+					}
+					$valueToWrite = $offsetValueType->setExistingOffsetValueType($offsetType, $valueToWrite);
 				}
-				$valueToWrite = $offsetValueType->setExistingOffsetValueType($offsetType, $valueToWrite);
 
 				if ($valueToWrite->isArray()->yes()) {
 					if ($hasOffsetType !== null) {
diff --git a/src/Type/IntersectionType.php b/src/Type/IntersectionType.php
index 2e5514dc02..7c6f215085 100644
--- a/src/Type/IntersectionType.php
+++ b/src/Type/IntersectionType.php
@@ -981,7 +981,12 @@ public function setOffsetValueType(?Type $offsetType, Type $valueType, bool $uni
 			}
 		}
 
-		if ($this->isList()->yes() && $this->getIterableValueType()->isArray()->yes()) {
+		if (
+			$this->isList()->yes()
+			&& $valueType->isArray()->yes()
+			&& $offsetType !== null
+			&& IntegerRangeType::fromInterval(0, null)->isSuperTypeOf($offsetType)->yes()
+		) {
 			$result = TypeCombinator::intersect($result, new AccessoryArrayListType());
 		}
 
diff --git a/tests/PHPStan/Analyser/nsrt/bug-10089.php b/tests/PHPStan/Analyser/nsrt/bug-10089.php
index 21122cdfc3..ff8d55eeed 100644
--- a/tests/PHPStan/Analyser/nsrt/bug-10089.php
+++ b/tests/PHPStan/Analyser/nsrt/bug-10089.php
@@ -22,7 +22,7 @@ protected function create_matrix(int $size): array
 		$matrix[$size - 1][8] = 3;
 
 		// non-empty-array<int, non-empty-array<int, 0|3>&hasOffsetValue(8, 3)>
-		assertType('non-empty-list<non-empty-array<int<0, max>, 0|3>>', $matrix);
+		assertType('non-empty-array<int, non-empty-array<int<0, max>, 0|3>>', $matrix);
 
 		for ($i = 0; $i <= $size; $i++) {
 			if ($matrix[$i][8] === 0) {
diff --git a/tests/PHPStan/Analyser/nsrt/bug-13629.php b/tests/PHPStan/Analyser/nsrt/bug-13629.php
new file mode 100644
index 0000000000..ee2724f4a1
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-13629.php
@@ -0,0 +1,37 @@
+<?php declare(strict_types = 1);
+
+namespace Bug13629;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @param array<string, list<array{xmlNamespace: string, namespace: string, name: string}>> $xsdFiles
+ * @param array<string, list<array{xmlNamespace: string, namespace: string, name: string}>> $groupedByNamespace
+ * @param array<string, list<string>> $extraNamespaces
+ */
+function test(array $xsdFiles, array $groupedByNamespace, array $extraNamespaces): void {
+	foreach ($extraNamespaces as $mergedNamespace) {
+		if (count($mergedNamespace) < 2) {
+			continue;
+		}
+
+		$targetNamespace = end($mergedNamespace);
+		if (!isset($groupedByNamespace[$targetNamespace])) {
+			continue;
+		}
+		$xmlNamespace = $groupedByNamespace[$targetNamespace][0]['xmlNamespace'];
+
+		assertType('string', $xmlNamespace);
+		assertType('non-empty-list<string>&hasOffsetValue(1, string)', $mergedNamespace);
+
+		$xsdFiles[$xmlNamespace] = [];
+		foreach ($mergedNamespace as $namespace) {
+			foreach ($groupedByNamespace[$namespace] ?? [] as $viewHelper) {
+				$xsdFiles[$xmlNamespace][$viewHelper['name']] = $viewHelper;
+			}
+		}
+		// After assigning with string keys ($viewHelper['name']), $xsdFiles[$xmlNamespace] should NOT be a list
+		assertType('array<int<0, max>|string, array{xmlNamespace: string, namespace: string, name: string}>', $xsdFiles[$xmlNamespace]);
+		$xsdFiles[$xmlNamespace] = array_values($xsdFiles[$xmlNamespace]);
+	}
+}