Well, that's it. I'm using winserver 2012 r2, chromium 34.0.1785.0 and the proxy itself mostly has minimal settings.
What's worth to note - antisocial list is downloaded successfully, which gives an assumption that this problem is somehow connected with particularly long lists that need to be split to different pieces while being transmitted - probably on application layer (i may be very wrong here, since im not too experienced).
Filters won't download through squid 3.3.3 proxy
Re: Filters won't download through squid 3.3.3 proxy
If this is still up to date, please file a detailed step by step issue at https://issues.adblockplus.org