BTW, chickenchunks chunk loaders have been known to cause chunk regens, which sounds like what happened to one of you. I had it happen to me recently on a MagicFarm2 server too, pretty annoying. It ate my whole 110 dynamo MFR laser drill setup and the 3 nearly full diamond chests it was feeding in to, and I wasn't able to get any of it back. Needless to say, it was annoying.
I know you guys are using the DW20 modpack, but I'd suggest switching over to dimensional anchors or something instead of chickenchunks if at all possible, especially if you don't have any easy way to restore lost chunks.