NV 200 SE Van

Hi

I have recently purchased a Nissan NV200 SE van.
Whenever I turn the ignition key to on, the immobiliser red security light pops up on the speedo for a few seconds then disappears (as it should do).
However, when it turn the vehicle off, and lock it up, should the light flash at regular intervals? According to the manual it should, however several of the same vehicles at my dealership don't do this either! Some do though! So what's up, is this normal or is something wrong with it?

Ps: dealer stumped too!

Thanks

DC