Someone

relevant sections of ~/.irssi/config:

servers = (
  {
    address = "irc.efnet.eu";
    chatnet = "efnet";
    port = "6667";
    autoconnect = "yes";
  },
  { address = "efnet.vuurwerk.nl"; chatnet = "efnet"; port = "6667"; },
  { address = "efnet.demon.co.uk"; chatnet = "efnet"; port = "6667"; },
  { address = "irc.du.se"; chatnet = "efnet"; port = "6667"; },
  {
    address = "chat.eu.freenode.net";
    chatnet = "opn";
    port = "6667";
    autoconnect = "yes";
  },
  { address = "orwell.freenode.net"; chatnet = "opn"; port = "6667"; },
  { address = "adams.freenode.net"; chatnet = "opn"; port = "6667"; },
  { address = "vinge.freenode.net"; chatnet = "opn"; port = "6667"; },
  {
    address = "Oslo.NO.EU.IRCLink.Net";
    chatnet = "irclink";
    port = "6667";
    autoconnect = "yes";
  },
  {
    address = "Tromso.NO.EU.IRCLink.Net";
    chatnet = "irclink";
    port = "6667";
  },
  {
    address = "Alesund.NO.EU.IRCLink.Net";
    chatnet = "irclink";
    port = "6667";
  },
  {
    address = "irc.perl.org";
    chatnet = "magnet";
    port = "6667";
    autoconnect = "yes";
  },
  { 
    address = "london.irc.perl.org"; chatnet = "magnet"; port = "6667"; },
  { address = "grou.ch"; chatnet = "magnet"; port = "6667"; },
  { address = "irc.hellyeah.org"; chatnet = "magnet"; port = "6667"; },
  {
    address = "xxx";
    chatnet = "29d";
    port = "6697";
    use_ssl = "yes";
    ssl_cert = "~/.irssi/ssl/client.crt.pem";
    ssl_pkey = "~/.irssi/ssl/client.key.pem";
    ssl_verify = "yes";
    ssl_cafile = "~/.irssi/ssl/ca.crt.pem";
  }
);
chatnets = {
  29d = { type = "IRC"; };
  efnet = { type = "IRC"; };
  opn = { type = "IRC"; };
  irclink = { type = "IRC"; };
  magnet = { type = "IRC"; };
};

The above is set before starting irssi. On startup, I get a number of the following errors (approx 10-15ish):

**process: (70861): CRITICAL **: config_node_find: assertion `is_node_list(node)' failed

irssi then complains about syntax errors in the config, which (i assume) is because the parsing is breaking somehow.

when i type /save, the chatnets block now looks like:

chatnets = {
  type = "IRC";
  efnet = { type = "IRC"; };
  opn = { type = "IRC"; };
  irclink = { type = "IRC"; };
  magnet = { type = "IRC"; };
  29d = { type = "IRC"; };
};
efnet = { type = "IRC"; };
opn = { type = "IRC"; };
irclink = { type = "IRC"; };
magnet = { type = "IRC"; };

Note, the "29d" chatnet moves to the bottom, all the entries that were below it are replicated outside the chatnet block, and an additional (broken) line is added where the "29d" chatnet used to be.

This behaviour is consistent wherever the "29d" chatnet is located in the channels block, e.g. if it was at the bottom the channels block would end up looking like:

chatnets = {
  efnet = { type = "IRC"; };
  opn = { type = "IRC"; };
  irclink = { type = "IRC"; };
  magnet = { type = "IRC"; };
  type = "IRC";
  29d = { type = "IRC"; };
}

If autosendcmd's are present in the "29d" chatnet it can cause a segfault, too.