diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/Method/ExistingAtomicMethodCallAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/Method/ExistingAtomicMethodCallAnalyzer.php
index c3f4717e3..62d63cec6 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/Method/ExistingAtomicMethodCallAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/Method/ExistingAtomicMethodCallAnalyzer.php
@@ -42,10 +42,13 @@ use Psalm\Type\Atomic\TTemplateParam;
 use Psalm\Type\Union;
 use UnexpectedValueException;
 
+use function array_filter;
 use function array_map;
 use function count;
 use function explode;
 use function in_array;
+use function is_string;
+use function strpos;
 use function strtolower;
 
 /**
@@ -422,30 +425,48 @@ class ExistingAtomicMethodCallAnalyzer extends CallAnalyzer
             }
 
             if ($method_storage->if_true_assertions) {
+                $possibilities = array_map(
+                    static fn(Possibilities $assertion): Possibilities => $assertion->getUntemplatedCopy(
+                        $template_result,
+                        $lhs_var_id,
+                        $codebase,
+                    ),
+                    $method_storage->if_true_assertions,
+                );
+                if ($lhs_var_id === null) {
+                    $possibilities = array_filter(
+                        $possibilities,
+                        static fn(Possibilities $assertion): bool => !(is_string($assertion->var_id)
+                            && strpos($assertion->var_id, '$this->') === 0
+                        )
+                    );
+                }
                 $statements_analyzer->node_data->setIfTrueAssertions(
                     $stmt,
-                    array_map(
-                        static fn(Possibilities $assertion): Possibilities => $assertion->getUntemplatedCopy(
-                            $template_result,
-                            $lhs_var_id,
-                            $codebase,
-                        ),
-                        $method_storage->if_true_assertions,
-                    ),
+                    $possibilities,
                 );
             }
 
             if ($method_storage->if_false_assertions) {
+                $possibilities = array_map(
+                    static fn(Possibilities $assertion): Possibilities => $assertion->getUntemplatedCopy(
+                        $template_result,
+                        $lhs_var_id,
+                        $codebase,
+                    ),
+                    $method_storage->if_false_assertions,
+                );
+                if ($lhs_var_id === null) {
+                    $possibilities = array_filter(
+                        $possibilities,
+                        static fn(Possibilities $assertion): bool => !(is_string($assertion->var_id)
+                            && strpos($assertion->var_id, '$this->') === 0
+                        )
+                    );
+                }
                 $statements_analyzer->node_data->setIfFalseAssertions(
                     $stmt,
-                    array_map(
-                        static fn(Possibilities $assertion): Possibilities => $assertion->getUntemplatedCopy(
-                            $template_result,
-                            $lhs_var_id,
-                            $codebase,
-                        ),
-                        $method_storage->if_false_assertions,
-                    ),
+                    $possibilities,
                 );
             }
         }
diff --git a/tests/AssertAnnotationTest.php b/tests/AssertAnnotationTest.php
index cd69d0eb9..eb3281bcb 100644
--- a/tests/AssertAnnotationTest.php
+++ b/tests/AssertAnnotationTest.php
@@ -2007,6 +2007,30 @@ class AssertAnnotationTest extends TestCase
                     function requiresString(string $_str): void {}
                 ',
             ],
+            'assertionOnPropertyReturnedByMethod' => [
+                'code' => '<?php
+                    class a {
+                        public ?int $id = null;
+                        /**
+                         * @psalm-mutation-free
+                         *
+                         * @psalm-assert-if-true !null $this->id
+                         */
+                        public function isExists(): bool {
+                            return $this->id !== null;
+                        }
+                    }
+
+                    class b {
+                        public ?int $id = null;
+                        public function __construct(private a $a) {
+                            if ($this->getA()->isExists()) {
+                                /** @psalm-check-type-exact $this->id = ?int */
+                            }
+                        }
+                        public function getA(): a { return $this->a; }
+                    }',
+            ],
             'assertWithEmptyStringOnKeyedArray' => [
                 'code' => '<?php
                     class A