I dont think this is fixed yet, but I cant test it, since I dont get disconnected by my ISP.
The article you mention would be this http://www.coindesk.com/bitcoin-nodes-need/ I guess.
These nodes disappear because people turn their computers off and not because their ISPs change the IP.
As these charts suggest https://getaddr.bitnodes.io/dashboard/
this is indeed a minor problem.
External IPs changing on an always-on connection should only affect a few users, perhaps a command line option to enable periodic polling of external IP would be the solution, so not everyone is hammering external IP service providers unnecessarily by default.
There seem to be several discussions going on about a possible solution.
You can reach most of them from here:
https://github.com/bitcoin/bitcoin/pull/3088
A possible workaround would be a cronjob that restarts bitcoin core every x hours.