E61, odd welcome lights.

[PLuKE]

I have come across an odd behaving welcome lights on my E61 LCI.

When I lock the car and unlock after being in the shop the welcome lights didn't come on, so I checked the iDrive and auto position for the headlights. Locked the car waited 5-10seconds and unlocked, all working!

But if I lock the car and wait 10-20 seconds it doesn't, seems odd!

Any ideas?

Thanks
Luke