It doesn’t really matter what vacuum breaker valve you fit, as long as it fits.
TTM It happens when the boiler is up to temperature.
Sorry, I’m not clear. It happens say, after the machine has been on for a while or only happens as it is warming up past 100C on the service boiler? Because if it is happen just briefly as the machine warms up as it nears 100C, then that’s standard behaviour, and you might just need to re-attach the silicone hose back to it, if you can.