93d80501 made execution of
ban_lurker_test_ban() conditional on bd != b, which effectively caused
objects hanging off bans below request bans to not get tested against
relevant bans.

Because object bans (from the obans list) are being marked completed,
the objects which were skipped would also be missed to get evaluated
against the relevant bans at lookup time unless they were evaluated in
request context. So, in effect, we would simply miss to test bans.

Fixes #3007

Maybe related to #3006