[Symbiote]

My Kubuntu desktop has IPv6, and I have no problems running apt.

I just updated from 2001:878:346::116 / mirrors.dotsrc.org; no problems.

Which mirror were you using, and did you file a report?

[GvS]

I used default mirrors and I didn't file a report because I'm not sure where and which part of the system is to blame. All IPv6 traffic was slow. This question is from 2 years ago so I assumed it's a known issue.