Current implementation using robots.txt for blocking indexing of /*controller=ai1ec_exporter_controller* causes warnings in Google Search Console. Google advises using noindex meta tags on relevant pages instead.
The URLs showing up in my coverage report are direct links to download iCalendar files. I don't think Google ever shows direct download links in results anyway, so maybe all you need to do is remove the line in robots.txt. Otherwise, you'll have to use HTTP headers (X-Robots-Tag: noindex) to block indexing because you're not serving HTML content from those URLs.