Error message: Probe Active handles has reached value null

[ivosabev]

I am constantly getting this error, could it be from Node version being 9.9.0?

Error message: Probe Active handles has reached value null

[petergi]

Same here. And I'm being bombarded with notification email. Problem is... the error message is just about useless since it doesn't tell me anything about the probe....
How to track this down?