only encode if current path is broken

middleman-core/lib/middleman-core/util/paths.rb

@@ -157,12 +157,16 @@ module Middleman
       end
 
       # Try to parse URL
+      begin
+        uri = URI(url)
+      rescue ::URI::InvalidURIError
         begin
           uri = URI(::URI.encode(url))
         rescue ::URI::InvalidURIError
           # Nothing we can do with it, it's not really a URI
           return url
         end
+      end
 
       relative = options[:relative]
       raise "Can't use the relative option with an external URL" if relative && uri.host