Startup functions client side not working

We have an urgent problem
Client side Meteor.startup functions are not running in production. In development they work correctly, even if we run the app with the --production flag.
They are basically ignored.

More info:
If we add in production a Meteor.startup function in the console, it gets executed

Meteor version: 1.5

Any clue?

Thanks in advance!

@benjamn @abernix