Describe the bug
Using a tinkers' construct fabric port called hephaestus and roughly enough items, the compat recipes added by create additions do not load correctly. When hovering the cursor over any inputs for the recipe with REI installed, the game crashes. I understand the crash is not the fault of create additions and I am also reporting this to REI, however I wanted to let you know about the recipe issues.

To Reproduce
With the required mods installed, look up the mixer recipes until you find one with an empty slot for an input ingredient in the leftmost slot in REI, hover your mouse over this.

Additional context
Mods used to create the issue:

Example of issue:

Log and crash report:
latest.log
crash-2024-04-03_21.40.10-client.txt

This is because the recipes are not marked as conditional when they should be. I don’t know which one is shown in the example from OP, but I’m seeing something similar (though thankfully without a crash) in EMI for electrum. It requires silver, but silver is not provided so it has an empty tag. It should have something like

"fabric:load_conditions": [
  {
    "condition": "fabric:tags_populated",
    "values": [
      "c:silver_ingots"
    ]
  }
]

(Note I have not tested this; I copied that from Hephaestus itself, minus a condition which C&A itself fulfills.)

This is because the recipes are not marked as conditional when they should be. I don’t know which one is shown in the example from OP, but I’m seeing something similar (though thankfully without a crash) in EMI for electrum. It requires silver, but silver is not provided so it has an empty tag. It should have something like

Thanks for the additional info, to answer your question about what recipe that is, it is for the queens slime ingot in the tconstruct folder under the compat recipes. I also found out after some more digging that the crash was caused by an issue directly with create fabric and REI/JEI however the problem was on create's end. It has already been fixed but they have not released an update with the fix yet. You can see the bug report here: create-fabric issue 1382.

Bumping this: The recipe for electrum is also bugged because it uses silver, but doesn't add silver to the game
So in REI it just appears as an empty recipe for the same reason @dhouck mentioned

Possible fix is to stop using forge: tags in the fabric build?

This is also an issue with Forge versions of the mods in 1.19.2.

I'd like to suggest leaving compatibility with Tinker's Construct to a different (dedicated) addon or mod so as to not affect the balance of either mod (there are multiple ways to handle compatibility) in this mod, which is primarily enjoyed for its electricity.