Inertia,
We have a FAQs page using an expanding layer - well coded and no problems otherwise, but Google has never liked the page, even though it contains great info, is user-friendly and has quite a few good links. It's at
Advice on Teaching English in Italy | FAQs for English Teachers working in Italy if you want to check it out.
My hunch is that if this isn't the only example on the site you're ok, but probably the text isn't contributing much SEOwise, but if it's the only example on your site G takes a second look and errs on the side of caution.
Take care,
Alex