Escort talent/activable item interaction is weird

[ghostbuster]

It you have an item that can be activated for a talent, the mastery of talent will be your own mastery in the corresponding tree.
It makes sense if you have a high mastery in the corresponding tree.
But this behavior is incoherent with talents that are gained from escorts.

For instance, if you get field-control/track from an escort, you armors of delving will be immediately degraded as you "gain" a 0.8 mastery in field-control.
It is even worse than that. Gaining track from an escort will also immediately degrade your boots of disengagement, as these talents belong to the same tree.

I don't know if the default mastery on items should be 1 or 0.8, but the interaction between items and escort-gained talents is clearly absurd.