Tvheadend

If you have "idle scan muxes' enabled, disable it.

I was battling this for a while (and I even killed my server for a few months, since i didn't have time to deal with it and it was just eating bandwidth) I'm on LTE so using 3.5tb a month is a quick way to get my account terminated! Luckily this happened in the middle of a merger so I guess I got away with it this time.

What you want to do is go into your configuration->dvb inputs->muxes tab, set it to view all instead of 50 on the bottom right, then select all of your (and only your) IPTV muxes (click first one, scroll to the end, then shift click the last one). Hit "edit", then for "EPG scan", select "disable", make sure you click the check box to the left to tell it you want to apply that to all of your selected entries.

I wish they'd add the ability to just specify this for an entire network, but this gets the job done in the meantime. You may want to do it every so often since new muxes will default to auto, but at least it gets rid of the constant scanning of everything all the time.