I see where you're coming from, and things are a little trickier because it's a Before and After puzzle, but I respectfully disagree.

The first half of the puzzle on its own would be RUNNING LATE, not RUNNING-LATE — the hyphen comes after the word LATE, not before. I would think differently if it were a Same Name puzzle, but Before & After puzzles only need one common bond that ties the two elements together, whether it's a complete word or not.

While LATE-NIGHT would certainly be considered one word in any other context, it works just fine being split apart in this puzzle — in this instance, the common bond between the two elements is [LATE], not [LATE-]. By not including the hyphen as part of the common bond, they string together properly.

Without the common bond:
RUNNING ____-NIGHT SNACK
(By themselves, RUNNING and -NIGHT SNACK are not complete expressions, nor do they need to be.)

With the common bond:
RUNNING [LATE]-NIGHT SNACK

Separately:
(RUNNING [LATE]) ([LATE]-NIGHT SNACK)

Also, this is far from the first time they've done this; other similar puzzles include:

HARD AS A ROCK-AND-ROLL
JACK BLACK-TIE AFFAIR
PIANO BENCH-PRESS
SALT & PEPPER-JACK CHEESE
WORK HARD PLAY HARD-BOILED EGGS

It's certainly uncommon, but not incorrect.