I just got only a masterwork chest and key out of a masterwork chest

From what it shows the chest and key are just bonus items and we are guaranteed a base item (skin, ward, etc..) I was an idiot confused at if it was intended and so I didn't have a screen shot of it but I am sure this is a bug, just thought i should let you know. Not really upset either since you know its like I only ever got one chest so w/e, but others might be upset.