Can someone help me decipher this error message? I'm struggling to figure out exactly what is duplicated?

• duplicate key value violates unique constraint "product_product_combination_unique" DETAIL: Key (product_tmpl_id, combination_indices)=(19812, ) already exists. at row 2 (Mega-Combo 4 Way Pocket Tool)
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The database has the proper product categories, attributes, and attribute values. There is only the one Product Template that I'm trying to add these variants to.