Multiple negated source search exclusion errors with invalid url parameter


We used to have this search query active as Saved Search and in our twitter clients (Twitter iOS, Tweetbot/OS X, via Zapier and other tools), but this query returns a ‘missing or invalid url parameter’ error for the last few days. When I use just one source: exclusion the query works fine, but multiple exclusions suddenly don’t work anymore. Was this changed this week? How can I filter these content bots from our search query?

(iPhoneclub OR iCulture) -#iCultureapp -from:iculture exclude:retweets -source:twitterfeed -source:ifttt -source:hootsuite -source:rsscockpit