okay try this: open a new project- (default template or no template)-o
draw a piece of wall- go into wall assembly and add a couple of layers
to that wall- unlock those layers- go back to that piece of wall in plan
and put a section through it and see how all the layers are still locked.

what locks and unlocks wall layers besides in wall assembly?

never mind- it's too complicated for anyone to talk about. it just
has to do with combinations and locations of layers on the wall
that you leave locked and ones you unlock. it will probably remain
a permanent mystery.