diff --git a/build/psalm-baseline.xml b/build/psalm-baseline.xml
index f43a9e4aa7b31..496f92d52f4d8 100644
--- a/build/psalm-baseline.xml
+++ b/build/psalm-baseline.xml
@@ -3807,14 +3807,7 @@
     </TypeDoesNotContainType>
   </file>
   <file src="lib/private/Files/Storage/Wrapper/Encryption.php">
-    <InvalidReturnStatement>
-      <code><![CDATA[$result]]></code>
-    </InvalidReturnStatement>
-    <InvalidReturnType>
-      <code><![CDATA[int]]></code>
-    </InvalidReturnType>
     <InvalidScalarArgument>
-      <code><![CDATA[$lastChunkPos]]></code>
       <code><![CDATA[$size]]></code>
     </InvalidScalarArgument>
   </file>
diff --git a/lib/private/Files/Storage/Wrapper/Encryption.php b/lib/private/Files/Storage/Wrapper/Encryption.php
index 4bc4d92661f2a..6f900ecf0bc69 100644
--- a/lib/private/Files/Storage/Wrapper/Encryption.php
+++ b/lib/private/Files/Storage/Wrapper/Encryption.php
@@ -406,7 +406,7 @@ protected function verifyUnencryptedSize(string $path, int $unencryptedSize): in
 	 * @param int $size size of the physical file
 	 * @param int $unencryptedSize size of the unencrypted file
 	 */
-	protected function fixUnencryptedSize(string $path, int $size, int $unencryptedSize): int|float {
+	protected function fixUnencryptedSize(string $path, int $size, int $unencryptedSize): int {
 		$headerSize = $this->getHeaderSize($path);
 		$header = $this->getHeader($path);
 		$encryptionModule = $this->getEncryptionModule($path);
@@ -441,8 +441,7 @@ protected function fixUnencryptedSize(string $path, int $size, int $unencryptedS
 		// calculate last chunk nr
 		// next highest is end of chunks, one subtracted is last one
 		// we have to read the last chunk, we can't just calculate it (because of padding etc)
-
-		$lastChunkNr = ceil($size / $blockSize) - 1;
+		$lastChunkNr = (int)ceil($size / $blockSize) - 1;
 		// calculate last chunk position
 		$lastChunkPos = ($lastChunkNr * $blockSize);
 		// try to fseek to the last chunk, if it fails we have to read the whole file
diff --git a/tests/lib/Files/Storage/Wrapper/EncryptionTest.php b/tests/lib/Files/Storage/Wrapper/EncryptionTest.php
index ddcfe5e89347f..d63c4dc00aa7d 100644
--- a/tests/lib/Files/Storage/Wrapper/EncryptionTest.php
+++ b/tests/lib/Files/Storage/Wrapper/EncryptionTest.php
@@ -456,6 +456,67 @@ public function testFixUnencryptedSizeUsesBlockSizeOfFileEncoding(): void {
 		);
 	}
 
+	/**
+	 * filesize() remembers a recalculated size and updates the file cache whenever the
+	 * remembered size is not identical to the cached one, which also dispatches an event.
+	 */
+	public function testFilesizeUpdatesRecalculatedSizeOnce(): void {
+		$module = $this->createMock(IEncryptionModule::class);
+		$module->method('begin')->willReturn([]);
+		$module->method('getUnencryptedBlockSize')->willReturn(6072);
+		$module->method('decrypt')->willReturn(str_repeat('a', 42));
+		$module->method('end')->willReturn('');
+
+		$header = ['cipher' => 'AES-256-CTR', 'signed' => 'true', 'oc_encryption_module' => 'UNIT_TEST_MODULE'];
+		$content = str_pad(Util::HEADER_START, $this->headerSize, '-') . str_repeat('x', 2 * 8192 + 100);
+		$stream = fopen('php://memory', 'r+');
+		fwrite($stream, $content);
+		rewind($stream);
+
+		$entry = new CacheEntry(['fileid' => 42, 'encrypted' => true, 'encryptedVersion' => 1, 'size' => 0, 'unencrypted_size' => 0]);
+		$cache = $this->createMock(ICache::class);
+		$cache->method('get')->with('file.003')->willReturnCallback(function () use (&$entry) {
+			return $entry;
+		});
+		$cache->expects($this->once())->method('update')
+			->willReturnCallback(function (int $id, array $data) use (&$entry): void {
+				$entry = new CacheEntry(array_merge($entry->getData(), $data));
+			});
+		$sourceStorage = $this->createMock(\OC\Files\Storage\Storage::class);
+		$sourceStorage->method('filesize')->with('file.003')->willReturn(strlen($content));
+		$sourceStorage->method('fopen')->with('file.003', 'r')->willReturn($stream);
+		$sourceStorage->method('getCache')->willReturn($cache);
+
+		$instance = $this->getMockBuilder(Encryption::class)
+			->setConstructorArgs(
+				[
+					[
+						'storage' => $sourceStorage,
+						'root' => 'foo',
+						'mountPoint' => '/',
+						'mount' => $this->mount
+					],
+					$this->encryptionManager,
+					$this->util,
+					$this->logger,
+					$this->file,
+					null,
+					$this->keyStore,
+					$this->mountManager,
+					$this->arrayCache,
+				]
+			)
+			->onlyMethods(['getHeader', 'getHeaderSize', 'getEncryptionModule'])
+			->getMock();
+		$instance->method('getHeader')->willReturn($header);
+		$instance->method('getHeaderSize')->willReturn($this->headerSize);
+		$instance->method('getEncryptionModule')->willReturn($module);
+
+		$expected = 2 * 6072 + 42;
+		$this->assertSame($expected, $instance->filesize('file.003'));
+		$this->assertSame($expected, $instance->filesize('file.003'));
+	}
+
 	/**
 	 *
 	 * @param string $source