elastomeric paint on exterior stucco wall is beginning to bubble.

That sounds about right. Elastomeric was supposed to be "the answer", but it traps moisture from inside the building. You have no choice but to ignore the problem or to strip the building and re-paint with a top-rated premium latex. Latex let's the building breathe and sweat normally. I've got latex on my almost 100-year stucco over brick and it's been a great 30-years so far of no fuss.