Strange noise - Macdee Wirquin Neo Air zero leak trap

[Lisa Mac]

Hi,
I had a Macdee Wirquin Neo Air zero leak trap fitted in a sink vanity unit in April this year. Today it has started making a noise which sounds like a whale blowing air through it's blowhole!! It's 'blowing every few minutes and is loud enough for me to hear from the room next door
Any ideas what this could be, and how it can be fixed please?
Thank you

 

[ShaunCorbs]

Do / have you had problems with the sink draining?

 

[Lisa Mac]

Do / have you had problems with the sink draining?

None at all. It is draining fine and there are no bad smells - just this weird eruption noise every few minutes