In Direwolf20's Episode 18 he mentioned the weird dirt that didn't stack properly. I had experienced this problem in 1.7 packs and have created a minimod that fixes the issue.The issue is that certain item drops have an empty NBT tag added to them at some point. From what, I don't know. I'll leave that to the modpack and mod devs. (Edit: Research shows that the faulty mod is Thaumic Tinkerer, I don't know if the bug is fixed in dev versions) This is simply a quick drop-in fix for those who want it. All this mod does is listen for whenever an item spawns in the world, and if it has an *empty* NBT data tag, it erases it thus allowing it to stack with others. This should be completely safe because it only erases NBT root tags that are empty, so no data should ever be lost. It has been used in a production world with no problems.No guarantees, as I obviously haven't tested against all edge cases. As always, take backups regularly!Download: https://dl.dropboxusercontent.com/u/2080675/[1.7.10]StackerFix-universal-1.2.jar (Forge 1230 and up)Source code (Yes it literally fits in a screenshot):