I have tried this on three sites which disappared on the January 24th update, and it worked on all three.

www.fleege.com disappeared under "billboard design".

Searching "allintext:billboard design", and it returns to #2 position. Searching "intext:billboard design" reveals the current search results.

Could this all be as simple as Google changing the default for search terms from "allintext:" to "intext:"????

If so, what can we do to get back?