Hi there, Hunter 3 here.
It works as intended. The fact that the pet can lock for so long isn’t a problem because the pet is pretty easy to stop EXCEPT when combined with scout.
Easy fix - Do not give invisibility to pets for Scout. This would solve this broken part of pvp. It would be nice if they would fix the 1-shot invisibility combinations that others are using too though, like bleeding, headshot and cannoneer.
The rest of the class is fine barring this broken and unfair interaction. When pets are visible all classes have the capabilities to counter them. The only class that significantly struggles to find counters is the Cleric tree. Swordies can use knockback/knockdown attacks, Wizards can easily cc them, Archers can Full Draw, and all of these classes can also just kill the pet pretty easily rendering the enemy player with 3 class ranks of lost skills.
But invisibility is definitely broken.