I do not recognize that bot/user agent: CFNetwork/596.2.3. Searching this User Agent Database: http://www.user-agents.org/cgi-bin/free-search.cgi?template=free-search-detail.html&dbname=allagents.csv&key2=id_a_f_150&action=searchdbdisplay does show that this is a legitimate bot/user agent.
I have no idea what Monotony/17 is. It does not show any results in a Google search.
I assume what this is is a custom bot scraping thing. Monotony/17 whatever that is is trying to scrape your Feed and it is being Forbidden by BPS. There are several plugins that allow someone to grab your entire Feed automatically and display your Feed on their website. I assume this is what is being attempted and being blocked by BPS.