Merge pull request #51984 from nextcloud/backport/51942/stable31

[stable31] fix(cache): always require updates if mtime is null

Author: blizzz

lib/private/Files/Cache/Watcher.php

@@ -118,7 +118,7 @@ public function update($path, $cachedData) {
 	public function needsUpdate($path, $cachedData) {
 		if ($this->watchPolicy === self::CHECK_ALWAYS or ($this->watchPolicy === self::CHECK_ONCE and !in_array($path, $this->checkedPaths))) {
 			$this->checkedPaths[] = $path;
-			return $this->storage->hasUpdated($path, $cachedData['storage_mtime']);
+			return $cachedData['storage_mtime'] === null || $this->storage->hasUpdated($path, $cachedData['storage_mtime']);
 		}
 		return false;
 	}