Use wolf vs plant, especially this week.
Toggling auto off will allow you to wait for plant to stop being invincible but if you have heroes that continually hit her with basic attacks like bard, she will be charged again by the time her white skill is done.
There is no glitch with plant, her skill acts like normal. The war buff makes her difficult to deal with, same as other heroes who benefit from war modifiers.
Moon's animation freeze is the problem, with moon's white active, plant's white skill can last for the whole duration of the fight. Without moon's animation freeze, plant can be vulnerable multiple times during the fight. She can be killed with the right heroes.
In short, choose the right team.