Purchased Larkwell Martinez Tactical Backpacks Disappeared

I researched and then purchased three Larkwell Martinez Tactical Backpacks. I began a mission, and dragged those backpacks into my loadout for the mission. When I arrived on the planet, the backpacks were gone. I ended the mission and returned to the station. The money I had spent was still gone, but there were no Larkwell Martinez Tactical Backpacks in my inventory.