diff --git a/src/Type/Constant/ConstantArrayType.php b/src/Type/Constant/ConstantArrayType.php
index 3853794348..38cbd0c7cb 100644
--- a/src/Type/Constant/ConstantArrayType.php
+++ b/src/Type/Constant/ConstantArrayType.php
@@ -734,7 +734,9 @@ public function unsetOffset(Type $offsetType): Type
 					$k++;
 				}
 
-				return new self($newKeyTypes, $newValueTypes, $this->nextAutoIndexes, $newOptionalKeys, TrinaryLogic::createNo());
+				$isList = $this->isList()->and(TrinaryLogic::createFromBoolean($i === count($this->keyTypes) - 1));
+
+				return new self($newKeyTypes, $newValueTypes, $this->nextAutoIndexes, $newOptionalKeys, $isList);
 			}
 
 			return $this;
diff --git a/src/Type/Constant/ConstantArrayTypeBuilder.php b/src/Type/Constant/ConstantArrayTypeBuilder.php
index a306833e8d..7604ad5b41 100644
--- a/src/Type/Constant/ConstantArrayTypeBuilder.php
+++ b/src/Type/Constant/ConstantArrayTypeBuilder.php
@@ -109,6 +109,9 @@ public function setOffsetValueType(?Type $offsetType, Type $valueType, bool $opt
 				}
 
 				$max = max($this->nextAutoIndexes);
+				if ($max !== count($this->keyTypes)) {
+					$this->isList = TrinaryLogic::createNo();
+				}
 
 				$this->keyTypes[] = new ConstantIntegerType($max);
 				$this->valueTypes[] = $valueType;
diff --git a/tests/PHPStan/Analyser/nsrt/array-is-list-unset.php b/tests/PHPStan/Analyser/nsrt/array-is-list-unset.php
index b14b8c97df..4c67982461 100644
--- a/tests/PHPStan/Analyser/nsrt/array-is-list-unset.php
+++ b/tests/PHPStan/Analyser/nsrt/array-is-list-unset.php
@@ -19,8 +19,11 @@ function () {
 	assertType('true', array_is_list($a));
 	unset($a[2]);
 	assertType('array{1, 2}', $a);
-	assertType('false', array_is_list($a));
+	assertType('true', array_is_list($a));
 	$a[] = 4;
 	assertType('array{0: 1, 1: 2, 3: 4}', $a);
 	assertType('false', array_is_list($a));
+	unset($a[3]);
+	assertType('array{0: 1, 1: 2}', $a);
+	assertType('true', array_is_list($a));
 };