NoteCache still growing

The NoteCache does not shrink so easily. In some cases, the NoteCache has grown to 650 entries, although the threshold is set at 50.
This can happen when Zeppelin is starting and a user starts a long running note during the Notebook Init Thread. The Notebook Init Thread now loads various Notes. However, the oldest note from the user cannot be removed because it is in use. The cache therefore grows very strongly above the threshold.