ScanDirInternal rather checks for . from the back of the filename, allowing for filenames with multiple instances.

Source/Atomic/IO/FileSystem.cpp

@@ -778,7 +778,7 @@ void FileSystem::ScanDirInternal(Vector<String>& result, String path, const Stri
     if (path.Length() > startPath.Length())
         deltaPath = path.Substring(startPath.Length());
 
-    String filterExtension = filter.Substring(filter.Find('.'));
+    String filterExtension = filter.Substring(filter.FindLast('.'));
     if (filterExtension.Contains('*'))
         filterExtension.Clear();