The New Discussions feed has not worked right for months. I thought I resolved this a month ago but it seems to be an issue once more.
See for example https://en.wikipedia.org/w/index.php?title=Wikipedia:WikiProject_Cognitive_science/Discussions&action=history. During August 2015 the bot got in some weird loop causing it to continuously post the same several discussions as though they were new. In debugging I manually updated the "last updated" database but the problem ostensibly solved itself. Then the bot went silent for a month and now (September 21) it's posting stuff from August as though it were new. Here is the crontab:
0,30 * * * * jstart -l release=trusty -N wpx_discussionspy -quiet -mem 500M /data/project/projanalysis/bin/python /data/project/projanalysis/wikiproject_scripts/new_discussions.py