Random Bow Spawn in Big Valley?

While hunting in RDR2, my dad noticed a white gun icon on the minimap and called me over. I checked it out and found a bow on the ground. He already had a bow in his inventory. I swapped the bow with a Varmint Rifle, and his inventory now showed only one bow. I checked rdr2map.com, and there’s no event in this area. It’s Chapter 6, so no Skinner Brothers, and it’s far from the Nightfolk. Any idea why this happened?

Bow Spawn