Problem with tooltip and “shared=true” with stackedArea

[Rck]

Hello Tech Team !

I got a problem, please load this Fiddle to see it:
https://jsfiddle.net/jzrdy72m/1/

I’m using a stackedArea graph with “shared: true” into tooltip.
I have some zone without data (ex: 40).
I have one scatter point with “Bug” tooltip.

The problem: When we are moving the mouse over the “40” line, the “bug” tooltip is displayed.
What I would like: No tooltip displayed, because there is no dataserie value here.

Note: With “shared: false”, there is no problem.