I've recently noticed that category.py has a problem with big categories and got down during getting categories or just before saving results. Today I treid to listify Category:Wikiprojekty at pl.wiki with recurse option and got something like this:
Getting [[Kategoria:WikiProjekt Pallotyni]]... Getting [[Kategoria:User projekt pallotyni]]... Getting [[Kategoria:Wikiprojekt Chopin]]... Getting [[Kategoria:Wikiprojekty]]... Creating page [[Wikipedysta:AlohaBOT/wiki]] via API HTTPError: 500 Internal Server Error WARNING: Could not open 'http://pl.wikipedia.org/w/api.php'. Maybe the server is down. Retrying in 1 minutes... HTTPError: 500 Internal Server Error WARNING: Could not open 'http://pl.wikipedia.org/w/api.php'. Maybe the server is down. Retrying in 2 minutes...
patrol