Was one of the two issues involving slavery in the Constitution?

Yes, one of the key issues involving slavery in the Constitution was the Three-Fifths Compromise, which determined that enslaved individuals would be counted as three-fifths of a person for purposes of representation and taxation. Additionally, the Constitution included a provision that allowed the continuation of the transatlantic slave trade for twenty years after its ratification, after which Congress could prohibit it. These compromises reflect the contentious nature of slavery in the early United States and the political negotiations surrounding its existence.