Stealth does not work consistently

[SevereOverfl0w]

user=> (pull {:a 1 :b {:a 2 :b 2 :c 3}} [{:b [:c]}] {:stealth #{:c}})
{:b {}}
user=> (pull {:a 1 :b {:a 2 :b 2 :c 3}} [:b] {:stealth #{:c}})
{:b {:a 2, :b 2, :c 3}}

In the latter case, because I am not explicitly recursing, but am treating the next part of the tree as a value, the stealth never "kicks in".