I've narrowed this down further, the increase in open files does not happen after receiving any old message, but "urn:xmpp:carbons:2" messages when clients other than gajim are messaging, using the same account and gajim is getting copies of those messages.
- Bug#1140358: Crash: GLib-ERROR **: Creating pipes for GWakeu... ArizonaRover
- Bug#1140358: Crash: GLib-ERROR **: Creating pipes for G... arizona.rover

