Seems to me they might not have changed the right vacuum valve or did it wrong or changed part of it. It's more than likely that PCV valve especially as it just all of a sudden started. The valve steam seals don't just start to do that one day...its a slow process.

You have to take the intake manifold off to do that repair so see if they did that. The valve is located on the very backside of the intake manifold.

__________________
2002 X5 4.4i Sport Wheels
2014 X5 35i M Appearance & suspension package
1995 Porsche 993
1972 Porsche 914-6
2020 GLE 450 Twin Turbo
2019 Alfa Stelvio 500hp Quadrifogilo
Many motorcycles