@Tim-C So sorry for bothering, but again, is directional light culling mask meant to work in LWRP ? If yes, what is the status of this feature that currently isn’t working ?
Answer is still pending for all those threads. For some it’s been for months 
Feedback Wanted: Scriptable Render Pipelines page-17
Furthermore I’m worrying because I see all strong issues I had on LWRP disappearing from the issue tracker for no explanation, for example:
-Unity Issue Tracker - [LWRP] Directional Light Culling Masks don't work properly
is considered as a duplicate and redirects to
-Unity Issue Tracker - [LWRP] Light layer culling not working
which does not exist anymore.
But I also have those who disappeared:
My question is: where are they? We have no any visiblity on that anymore. And the lack of clarity is very frustrating 
Thanks for your answer.