Title says it all.

I have a 2013 BMW 328i, over the last little while my car has had some battery issues so I thought it was time to get a new battery.

I installed a new battery today, got it programmed and to my surprise I got a message on the dash saying “battery drained while stopped” which is hinting at a parasitic drain.

I opened the hood and it sounded like the intake manifold was still running (heard a vacuum noise) so I disconnected the battery to prevent my car being dead.

Has anyone experienced this before? And if so, would I need a whole new intake or could it possibly be just a bad relay?