So I noticed this problem 8/11/2017 and at first I blamed the mod uppers. You could place any item into the crafting grid that didn't normally have a result when placed there and it would result in a hopper from uppers.

When Removing the mod the result from any such item in the crafting grid became a basic machine casing from IC2.

After deactivating all the mods, I turned them back on one by one. I narrowed the source of it down to
Techreborn 1.12.2-2.8.1.342
Reborncore 3.4.11.153
IC2 2.8.16-ex112
+Forge version equal or higher than 14.23.0.2532
The changelog for that version mentioned
"Build 1.12.2-14.23.0.2532:
zzzz:
Fix the incorrect matching algorithm in ShapelessRecipes and
ShapelessOreRecipe (#4472)"

Downgrading the forge version below 14.23.0.2532

Fixes the bug. Though there is still visible in JEI

That nothing in the grid = a basic machine casing (when hovering over it with the mouse it says recipe by tech reborn)

humm, strange. Ill have to take a look at this.

I hope this one is fixed. )
Feel free to reopen if not

I think the team from applied energistics might know something about it because their latest version has

"Fixes #3200: Cleanup recipe factories to prevent recipes from not working on servers with forge version 2532 or later. - fscan"

In the changelog pertaining to the change in forge.

Maybe forge will fix this.

https://github.com/MinecraftForge/MinecraftForge/pull/4472/files#r146108157

Latest forge 2542 does not fix this.

I can still turn a block who has no 1x1 recipe normally into basic a machine casing.

The recipe to turn a tech reborn basic machine frame into an IC2 basic machine casing also doesn't shown up in JEI. Only a blank crafting grid = IC2 basic machine casing

Might I suggest checking the code for the recipe in your mod. Just in case something went wrong?

I hope issue fixed in TR in this commit: 53c8033

Updated version of TR is not released to curse yet.

Is indeed fixed. Thanks for all the help.