In the past week we’ve seen a weird spate of surprise career moves in the music business — most people thought the coup de grace was Brian McKnight’s new “Adult Mix Tape,” in which the renowned crooner used his soulful pipes for secular purposes. (Not kidding — “If You’re Ready to Learn” might tackle “other sexual type things,” but the chord changes are poached straight from gospel.) Slightly less shocking, but equally fascinating, is the latest single from POP ETC, the Berkeley-born, Brooklyn-based indie band formerly known as The Morning Benders. It’s an Auto-Tune-sluiced, cleanly-produced, snare-and-clap-clap R&B track with lyrics about a one night stand.