Exhaust smoke from Oil filler cap

[NA Radium]

I have just opened my oil filler cap after a 20 mile drive from a cold start and noticed some exhaust smoke coming out of the cap. Is this normal / expected?

2013 Citroën C4 1.6 e-HDI. 42k on the clock.


https://youtu.be/vkO8_x9adGQ

Thanks.