It has been found that the plasma cannon from the powersuit mod has an unpleasant side effect of disintegrating the inventory of any player killed by it, much like the way the force fields do from the MFFS mod. Since it was unknown before, the first time this happened resulted in a refund. Don't shoot you're friends, stuff may not be refunded from here on out for being an idiot and ignoring this information.
As a side note, if it disintegrates player inventories, it probably does the same to mob drops. Just a heads up.