Modpack version
1.62

Can the issue be reproduced?
Yes

Logs
https://github.com/Endlessgem/Crashreports/blob/master/crash-2019-04-22_14.35.54-client.txt

Issue
I can't use Builder's Wands and Building Gadgets or the game will crash.
Not sure if it's Thermal Expansion's Satchel problem.

Do you have a Resonant Satchel from Thermal Expansion on you?

I've been using the Building Gadget, Exchanging Gadget and Destruction Gadgets for a few weeks without any issues. Running 1.62 stock without changes.

Do you have a Resonant Satchel from Thermal Expansion on you?

Yes, I can use Building Gadget as usual after I delete my Resonant Satchel.

Thanks, I'll ask the Building Gadget folk to have another look at it.

It doesn't happen outside of E2E, so it's on us, and I haven't got any idea what could be modifying the Satchel unfortunately.

Huh, that's strange. I was able to reproduce it with only one attempt - Guess I need to check again :P

Is there more to it than just having a Building Gadget and a satchel in your inv? I can tell you that it definitely didn't recognise the TE satchel as a valid "container"

Is there more to it than just having a Building Gadget and a satchel in your inv? I can tell you that it definitely didn't recognise the TE satchel as a valid "container"

No, just Building Gadgets and a satchel.

Is there more to it than just having a Building Gadget and a satchel in your inv? I can tell you that it definitely didn't recognise the TE satchel as a valid "container"

Are you sure you're in survival mode? It's won't happen in creative mode.

Yup, definitely was in survival mode

I'm also using a Resonant Satchel (with Holding IV) and I'm not getting any issues with Building Gadgets? Does it crash for you with ANY satchel, even newly spawned in ones?

Could you try with a new Satchel that isn't enchanted Max?

Can't reproduce it, sorry :/

I'm gonna try some other edge cases later, maybe I'll actually be able to reproduce it at some point

I am experiencing the same crash. I don't have a Building Gadget but I do have a dank/null/.

Soon after I crafted the Resonant Satchel (Enchanted with Holding IV and XP Boost III) and opened a chest, my client crashed. same (ArrayIndexOutOfBoundsException: 45) as mentioned in OP.
I suspected it was the satchel, so I placed it in a chest and left it there till today, when I decided to confirm it really was the satchel, so went back to the chest and again. same crash. I am playing on a server.

Huh... interesting. Which mod errored in your case, though?

Crash Log: https://pastebin.com/B8UuW8iq

Pastebin

Satchel Crash - Pastebin.com

Now that's interesting. You said you don't even have a Building Gadget?

Well, I do, in another backpack, but not in my main inv at time of crash.

So it wasn't in a Satchel or anything that happened to be in your inv either?

Oh actually. they are in the Cyclic Extended inv.

Huh... I think I'm gonna leave it to the Building Gadgets team here since I feel like I wouldn't contribute much to the discussion right now, but that's... interesting

The issue has unfortunately been marked as "unresolved" on the Building Gadgets issue tracker, but we could still just try and see whether the latest version at least fixes OP's issue

Great find!

TL;DR for anyone being referred here:
Various mechanics that look in satchels, bags and extended inventories are treating Thermal Expansion satchels as if they have IItemHandlers registered, even though they do not.

This means that an unknown mod in Enigmatica 2: Expert is most likely assigning an IItemHandler to Thermal Expansion Satchels.

Common Capabilities does something with Thermal satchels, that may be worth looking into