Stepping fails inside quasiquoted forms

The following code runs as expected when not stepping, returning the map {:a "foo", :b "bar"}:
`(ns foo.core)

(defn foo []
   (let [a "foo"
          b "bar"]
      `{:a ~a
        :b ~b}))
`
When I step into the quasiquoted form, :a is evaluated and prints on the screen. But when I try to step into, out of, or over the unquoted form ~a, the stepper hangs.