What potential issue arises from the high intelligence of both terriers regarding training?

Answer

They can rapidly learn undesirable behaviors if the owner is inconsistent

Because they learn quickly, if an owner is inconsistent, these intelligent dogs can master and repeat unwanted behaviors just as fast as they master desired commands.

What potential issue arises from the high intelligence of both terriers regarding training?

#Videos

Fox Terriers, Jack Russells, Tenterfield, Japanese and ... - YouTube

DogbreedTenterfield TerrierJack Russell