N54 puff of blue/white smoke on startup?

So I asked the other half to move the car back into the drive today as I was covered in paint from DIY. As I stood behind the car, the OH started it up. The usual N54 twin exhaust loud note was followed by the usual click as the right side exhaust flap closed to quiet it down. The engine had been running for around 1 second before the valve closed as usual and as the valve closed on the right side tailpipe I noted a small puff of white/blue smoke from the left tailpipe. So the weird thing to me is that if this was oil leaking into the cyls somehow, that white/blue smoke, I'd expect, would be puffed out as soon as the engine started. In this case the puff of smoke was 1-2 seconds after the engine had started.



It was a very small puff of smoke, but I noted it nonetheless. Now I'm quite fastidious about the car and it uses no oil that I'm aware of (26K miles) so I'm wondering if this little puff of smoke is normal ish and I've just never seen it because I've never been behind the car when someone else started it up.



Any N54 peeps on here that could comment? Reading online it could be anything from normal to turbo seals, valve seals etc etc. The car does do very very short journeys every day and I'm wondering if these short journeys could be causing premature wear somewhere. Quite how I'd address that anyhow is another matter.