The third time’s the third charm for Olivia Rodrigo, who is beginning to look like she might be constutionally incapable of not turning in one of the year’s most diverting albums, in any given try. Not many artists have started off with as smashing a three-peat as Rodrigo and her producer/co-writer partner Dan Nigro, who’ve pulled it off again with “You Seem Pretty Sad for a Girl So in Love.” But just what the “again” entails here involves some wrinkles, since the departures taken go far beyond just dispensing with one-word titles. After two terrific but roughly similar albums, “Sour” and “Guts,” their inevitable task was to stray a bit from signature sounds and firmly establish they intend to not be a one-trick pony. Even if the initial trick was pretty great.

The big initial revelation upon a first listen to “You Seem Pretty Sad for a Girl So in Love” is that Rodrigo and Nigro have done a clever trade. The pop-punk style of the most ferocious parts of the first two albums is gone, as promised… but the rock isn’t. At least not if you consider “The Roq of the ’80s [or ’90s]” — to quote the old slogans for L.A.’s KROQ-FM — to be rock. About half the album involves a revival of those classic new wave sounds, something that was at least hinted at when the lead single, “Drop Dead,” employed a mid-song synth line that threatened, briefly but delightfully, to turn it into a Flock of Seagulls tune. Friends, there is more where that came from, and if you long for that slightly pre-grunge period where giant synth riffs and drum machines ruled rock, there are roughly a half-dozen songs that will put a goofy grin on your face. Listening to the album’s penultimate track, “Expectations,” I thought, “Missing Persons? Found!” It’s slightly goofy, and wholly wonderful.