To reproduce this situation, it is necessary to know the unbound ( DNS ) settings and the upstream proxy settings.
The unbound errors show some other problem with DNS, IMO.
EDIT: I’ve put cisco.com in RPZ’s blocklist. If I do a HTTP request I get 4 block messages ( one for my PC; 3 for 127.0.0.1, the proxy I suppose ) in the first access, each further try produces 2 messages.