Quest Blueleaf Tubers is impossible to complete

[Alaric]

When attempting to complete Blueleaf Tubers quest you are supposed to use item Crate With Holes inside trench in Razorfen Kraul to summon pet that will then reveal nodes from which quest item can be looted. However attempting to use the Crate inside the trench causes error message "Requires Nearby Tubers" to appear and no pet is summoned.

 

How to repead the bug.
Enter trench in Razorfen Kraul with Blueleaf Tuber quest active and use Crate with Holes.