interesting question...

i am tempted to say that it would react the same way as with the regular stucco (just fine), however some may come to the surface and affect the colors and that may not be good.

Why would you use pressure treated lath? I understand that it suppose to last longer in the dump condition, but the dump condition (if plaster is dump for a prolonged period of time) will destroy the plaster on it's own before any lath goes bad... Getting wet and dry (as exterior wall) is fine - just makes the wall stronger, but dumpness is a plaster killer.

So, really using pressure treated lath is an overkill that does not make the wall to last longer.