Hi Malorolam,
This an issue I've been having and thought I'd keep you updated with it
zerofall/EZStorage2#42

I gave the issue a quick whirl with just EZStorage and Lootbags and I couldn't duplicate the bug from the steps you gave in the other issue. If you can give me more precise instructions on exactly how you cause the issue with my bags, starting from loading the game, including what items are in your inventory then I might be able to help more. Just from what you posted, it sounds like something is causing a desync, so the item isn't the same on both client and server and not opening the gui.

It's a bit complicated... When I first enter minecraft the loot bags I have drop the items they hold in them. Once I go into the EZStorage 2 inventory and move the loot bags to my main hand slots, then quit out of the inventory GUI, right-click the bag nothing drops out of it. I do this multiple times and not a thing drops out of it. What usually happens is that restarting minecraft seems to work again until the issue resurfaces again. Of course when I look into the characters personal inventory the items have reshuffled back to their original spots before I moved them around.

EDIT: I will do a bit of digging myself seeing as how I've done this countless times before. It might be something else entirely. I will get back to you a bit later when I've found out what the issue is or what it might be. I will be updating you on the progress as it happens.

EDIT 2: Newest version of minecraft Forge (2110/1) causes a crash when using Lightning craft 2.6.0 for minecraft 1.10.2. The mod author has been made aware of the issue.

Of course when I look into my personal inventory then items have resuffeld back to their original spots before I moved them around.

Edit: Issue fixed itself after a crash occured concerning LightningCraft and forge version 2111. Thanks atleast for troubleshooting the issue along side me and Pegbeard

It was the telepads mod all along causing the desync issue. Everything is fine before using the teleporters. After that the desync issue is occuring