I encountered some interesting issues with purchasing the “random” chests from the collector.
In the interest of breaking the beta I gave myself many collector coins.
I purchased 1 Iron Outpost chest from the collector. It opened fine and gave loot.
I then purchased several (more than one) at a time by choosing to purchase 5 at once, rather than buying 1 chest 5 times.
None of these chests had any loot in them.
I returned to the store and bought 1 chest 5 times and each worked as expected.
I’m not sure if the game is generating the loot when the chest is bought and failing somehow, but it seems that if you buy multiple Iron Outpost chests at once they become useless items.