When the policy decision is set by the client to PolicyIgnore, there's no code to clear the pending API request (though clearly no API request is pending any more). Then if the client asks for it later via WKPageCopyPendingAPIRequestURL, a non-null answer is returned, which fools the client into thinking that some sort of load is still underway.
This is in Radar as <rdar://problem/9925931>
Created attachment 103420 [details]
Patch to clear the pending API request when PolicyIgnore is received.
Fixed in <http://trac.webkit.org/changeset/92729>.
I r+’ed my own patch in a moment of absent-mindedness. However, Anders Carlsson also gave me an r+, so I will still be able to sleep at night.