Describe your proposed suggestion.
Spelunkery completely overhauls mining, adding ingots nuggets to all ores that don’t have them already. In addition, mining an ore drops the raw metal, and occasionally also raw metal ingots nuggets. However, even with AlmostUnified installed, I end up with two unique copper ingot nugget recipes (because they have different textures I think).

Yeah, my bad, it sure is a nugget. Had a brain fart when I was typing

What copper ingot recipes are you speaking of? Drop some screenshots, if you wouldn't mind.

They should be the same thing, but they don't appear to for some reason. When Polymorph is disabled, it appears as two distinct crafting recipes.

That is a copper nugget recipe, not a copper ingot recipe. I will ask AU what they think of this, and if I need to tag my nuggets to get them to merge.

I believe setting the common tag is what needed to be done, here. It's been a while. The 1.21 release of this mod will include those tags. Feel free to retest in the latest release and see if that's the case! If not, of course, let me know.