E46 330Ci - is this a normal noise?

[Funk]

Noticed the car made this noise when turning off earlier and never noticed/heard it before. A quick search on various fora seems to return a mix of answers from 'it's normal' to possible DISA unit issues. Should I be getting this looked at or is it just something I've never noticed before? Not sure if it does it every time either, it did on the couple of restarts I did this afternoon.

https://youtu.be/E5u9EHGq39w

Thoughts appreciated! The car is a 2004 E46 330Ci.

[Sticks.]

My 04 Z4's done something similar for years. More of a 'quack' though lol. Everything works OK, I just put it down as a character.

Eta, it does it with the aircon on or off.

[Funk]

Cheers Sticks, strange I'd never noticed it before.

I've just had some work done on the cooling system (new thermostat, header tank, replaced a load of deteriorating pipework) so various bits and pieces have been in and out of the car for that work to be done. Wondered if something hadn't been put back quite right...