I tried to send a campaign using the newsly installed version 3.2 yesterday. The sending process failled, remaining stuck in a dead loop.
I then upgraded to version 3.2.1, which is supposed to address this issue. Unfortunately, it did not make a change; whenever I try to send a campaign, I have to refresh the page in order to send the next batch of emails.
As far as I understand from my router, I do not have ipv6 address. In addition, I’m using last phplist version, so the patch mentionned in your link is applied.