Noticed this in my log it has appeared at least twice (I did not go down the full log list to check for more) I have looked on DogNzb Forums and cannot seem to find anyone reporting this so perhaps it might be an issue on NzbDrone end
noticed this also since the last update
at first i thought DogNzb changed their API again but nothing new about that on their forums only posts from a couple months back went they changed it nothing in the last week or two
the tv seasons are in between at the moment so not really any shows i am getting right now to see if it is preventing API calls or grabbing of NZB’s but just an issue i noticed and thought i would mention it clearly not alone in it so that is good not my setup then 
It’s an invalid character in the feed coming back from dognzb, unrelated to the update. If you load the URL in your browser you will see it fail there as well as its invalid XML/RSS.
You will need to report the issue to them, the title looks like this in the feed: <title>Bones.S09E01.The.Secrets.In.The.Proposol</title>
alright i have posted it in the forums along with a quote of your last reply hopefully they can fix it