I think in some way, Google bot behaves as a headless browser (a la PhantomJS albeit their own special sauce). Their goal is to mimic an actual human user visiting a web page so even JavaScript may be getting parsed/evaluated so dynamically included text may also may get indexed.

In a similar vein, "invisible to user" text may get cross referenced with "visible to bot" text and if there's a discrepancy, that may count against your rank.