Fix validation typo

A typo in the validation method caused the validation loop to end early. Since this loop returns a list of valid routes, early termination meant some routes were left out. Which routes were left out was effectively random, as it's iterating over a set, so it's up to the whims of Python's hashing and iteration implementation.

The simple solution was to switch a single "break" to "continue". The piece of code was originally inside a nested loop, and when I pulled it out, I missed making the switch.