Still not totally clear - Are we talking about inside or outside?

Definitely no recourse (Legal, warranty or anything) You fix it its
yours.

I do not know what "prefab plaster" or "metallic trellis base" is
either.

Some of what you describe makes us think exterior, that's why SQLit
mentions stucco, an exterior masonry product. Some of what you describe
makes me think interior (plaster is used for interior wall finishes and
is more or less common depending on where you live)

Water infiltration could be the cause of what you describe, regardless
of interior or exterior.

Lets spend a bit of time on terms and better description of the problem
so we can all be on the same page.

Stucco - Exterior masonry finish, generally has some texture, applied
in layers. Usually has a wire lath for attachment.
Lath - First step for stucco or some plaster finish techniques
Wire lath - lath made of wire common with stucco, very unusual for
interior plaster jobs except for maybe some south west adobe looking
projects.
Wood lath - lath made of wood, common on really old houses.
Blue board - common underlayment for modern 'veneer plaster'
applications.
Veneer plaster - plaster applied over a gypsum board, similar to
drywall, commonly called blue board.
Plaster - basically gypsum and water - does not shrink. Used to make
some moldings as well as wall finishes. Interior use only.
Parge - This term may be regional. A masonry mortar skim coat over,
usually, a block wall to give a smooth finish. Sort of similar to
stucco but not textured and probably a higher Portland cement content,
not lath is used.

OK, now can you use these terms, as appropriate, to describe your
problem. Please tell us if its outside or inside, high on the wall or
low. Near a window or any other commonality. Load bearing wall is
interesting observation but may or may not be relevant. We'll see.

Pictures may be useful too.