Hi Justin:
I have a client with this problem. All of the filter URLs are crawled by Moz, show as duplicate content in Moz, have 302 warnings in Moz. All of them canonical back to their respective category pages. None appear on WMT/Search Console, but doing a similar "site:URL" search on Google shows they are indexed. I'm curious what you've done in the last year to resolve this? Or have you only tried to resolve via Sitemap submission, and did that work for you? Thank you!