diff --git a/lib/private/Files/Cache/Scanner.php b/lib/private/Files/Cache/Scanner.php
index 9f99bbaab2bf2..fd1aba9f99ba1 100644
--- a/lib/private/Files/Cache/Scanner.php
+++ b/lib/private/Files/Cache/Scanner.php
@@ -203,7 +203,9 @@ public function scanFile($file, $reuseExisting = 0, $parentId = -1, $cacheData =
 						$fileId = $cacheData['fileid'];
 						$data['fileid'] = $fileId;
 						// only reuse data if the file hasn't explicitly changed
-						if (isset($data['storage_mtime']) && isset($cacheData['storage_mtime']) && $data['storage_mtime'] === $cacheData['storage_mtime']) {
+						$mtimeUnchanged = isset($data['storage_mtime']) && isset($cacheData['storage_mtime']) && $data['storage_mtime'] === $cacheData['storage_mtime'];
+						// if the folder is marked as unscanned, never reuse etags
+						if ($mtimeUnchanged && $cacheData['size'] !== -1) {
 							$data['mtime'] = $cacheData['mtime'];
 							if (($reuseExisting & self::REUSE_SIZE) && ($data['size'] === -1)) {
 								$data['size'] = $cacheData['size'];
@@ -220,6 +222,11 @@ public function scanFile($file, $reuseExisting = 0, $parentId = -1, $cacheData =
 
 						// Only update metadata that has changed
 						$newData = array_diff_assoc($data, $cacheData->getData());
+
+						// make it known to the caller that etag has been changed and needs propagation
+						if (isset($newData['etag'])) {
+							$data['etag_changed'] = true;
+						}
 					} else {
 						// we only updated unencrypted_size if it's already set
 						unset($data['unencrypted_size']);
@@ -388,16 +395,20 @@ protected function getExistingChildren($folderId) {
 	 * @param int|float $oldSize the size of the folder before (re)scanning the children
 	 * @return int|float the size of the scanned folder or -1 if the size is unknown at this stage
 	 */
-	protected function scanChildren(string $path, $recursive, int $reuse, int $folderId, bool $lock, int|float $oldSize) {
+	protected function scanChildren(string $path, $recursive, int $reuse, int $folderId, bool $lock, int|float $oldSize, &$etagChanged = false) {
 		if ($reuse === -1) {
 			$reuse = ($recursive === self::SCAN_SHALLOW) ? self::REUSE_ETAG | self::REUSE_SIZE : self::REUSE_ETAG;
 		}
 		$this->emit('\OC\Files\Cache\Scanner', 'scanFolder', [$path, $this->storageId]);
 		$size = 0;
-		$childQueue = $this->handleChildren($path, $recursive, $reuse, $folderId, $lock, $size);
+		$childQueue = $this->handleChildren($path, $recursive, $reuse, $folderId, $lock, $size, $etagChanged);
 
 		foreach ($childQueue as $child => [$childId, $childSize]) {
-			$childSize = $this->scanChildren($child, $recursive, $reuse, $childId, $lock, $childSize);
+			// "etag changed" propagates up, but not down, so we pass `false` to the children even if we already know that the etag of the current folder changed
+			$childEtagChanged = false;
+			$childSize = $this->scanChildren($child, $recursive, $reuse, $childId, $lock, $childSize, $childEtagChanged);
+			$etagChanged |= $childEtagChanged;
+
 			if ($childSize === -1) {
 				$size = -1;
 			} elseif ($size !== -1) {
@@ -410,8 +421,17 @@ protected function scanChildren(string $path, $recursive, int $reuse, int $folde
 		if ($this->storage->instanceOfStorage(Encryption::class)) {
 			$this->cache->calculateFolderSize($path);
 		} else {
-			if ($this->cacheActive && $oldSize !== $size) {
-				$this->cache->update($folderId, ['size' => $size]);
+			if ($this->cacheActive) {
+				$updatedData = [];
+				if ($oldSize !== $size) {
+					$updatedData['size'] = $size;
+				}
+				if ($etagChanged) {
+					$updatedData['etag'] = uniqid();
+				}
+				if ($updatedData) {
+					$this->cache->update($folderId, $updatedData);
+				}
 			}
 		}
 		$this->emit('\OC\Files\Cache\Scanner', 'postScanFolder', [$path, $this->storageId]);
@@ -421,7 +441,7 @@ protected function scanChildren(string $path, $recursive, int $reuse, int $folde
 	/**
 	 * @param bool|IScanner::SCAN_RECURSIVE_INCOMPLETE $recursive
 	 */
-	private function handleChildren(string $path, $recursive, int $reuse, int $folderId, bool $lock, int|float &$size): array {
+	private function handleChildren(string $path, $recursive, int $reuse, int $folderId, bool $lock, int|float &$size, bool &$etagChanged): array {
 		// we put this in it's own function so it cleans up the memory before we start recursing
 		$existingChildren = $this->getExistingChildren($folderId);
 		$newChildren = iterator_to_array($this->storage->getDirectoryContent($path));
@@ -469,6 +489,10 @@ private function handleChildren(string $path, $recursive, int $reuse, int $folde
 					} elseif ($size !== -1) {
 						$size += $data['size'];
 					}
+
+					if (isset($data['etag_changed']) && $data['etag_changed']) {
+						$etagChanged = true;
+					}
 				}
 			} catch (Exception $ex) {
 				// might happen if inserting duplicate while a scanning
diff --git a/lib/private/Files/ObjectStore/ObjectStoreScanner.php b/lib/private/Files/ObjectStore/ObjectStoreScanner.php
index d827662ae0b1a..8a9b844c47fad 100644
--- a/lib/private/Files/ObjectStore/ObjectStoreScanner.php
+++ b/lib/private/Files/ObjectStore/ObjectStoreScanner.php
@@ -39,7 +39,7 @@ public function scan($path, $recursive = self::SCAN_RECURSIVE, $reuse = -1, $loc
 		return [];
 	}
 
-	protected function scanChildren(string $path, $recursive, int $reuse, int $folderId, bool $lock, int|float $oldSize) {
+	protected function scanChildren(string $path, $recursive, int $reuse, int $folderId, bool $lock, int|float $oldSize, &$etagChanged = false) {
 		return 0;
 	}
 
diff --git a/tests/lib/Files/Cache/ScannerTest.php b/tests/lib/Files/Cache/ScannerTest.php
index e4c052f602527..22d458a4a9b1b 100644
--- a/tests/lib/Files/Cache/ScannerTest.php
+++ b/tests/lib/Files/Cache/ScannerTest.php
@@ -404,4 +404,48 @@ public function dataTestIsPartialFile() {
 			['/sub/folder/foo.txt', false],
 		];
 	}
+
+	public function testNoETagUnscannedFolder() {
+		$this->fillTestFolders();
+
+		$this->scanner->scan('');
+
+		$oldFolderEntry = $this->cache->get('folder');
+		// create a new file in a folder by keeping the mtime unchanged, but mark the folder as unscanned
+		$this->storage->file_put_contents('folder/new.txt', 'foo');
+		$this->storage->touch('folder', $oldFolderEntry->getMTime());
+		$this->cache->update($oldFolderEntry->getId(), ['size' => -1]);
+
+		$this->scanner->scan('');
+
+		$this->cache->inCache('folder/new.txt');
+
+		$newFolderEntry = $this->cache->get('folder');
+		$this->assertNotEquals($newFolderEntry->getEtag(), $oldFolderEntry->getEtag());
+	}
+
+	public function testNoETagUnscannedSubFolder() {
+		$this->fillTestFolders();
+		$this->storage->mkdir('folder/sub');
+
+		$this->scanner->scan('');
+
+		$oldFolderEntry1 = $this->cache->get('folder');
+		$oldFolderEntry2 = $this->cache->get('folder/sub');
+		// create a new file in a folder by keeping the mtime unchanged, but mark the folder as unscanned
+		$this->storage->file_put_contents('folder/sub/new.txt', 'foo');
+		$this->storage->touch('folder/sub', $oldFolderEntry1->getMTime());
+
+		// we only mark the direct parent as unscanned, which is the current "notify" behavior
+		$this->cache->update($oldFolderEntry2->getId(), ['size' => -1]);
+
+		$this->scanner->scan('');
+
+		$this->cache->inCache('folder/new.txt');
+
+		$newFolderEntry1 = $this->cache->get('folder');
+		$this->assertNotEquals($newFolderEntry1->getEtag(), $oldFolderEntry1->getEtag());
+		$newFolderEntry2 = $this->cache->get('folder/sub');
+		$this->assertNotEquals($newFolderEntry2->getEtag(), $oldFolderEntry2->getEtag());
+	}
 }