If it helps Draconic Destiny, Platoon Dispenser, and In the Trenches where the Mythics from Brothers War it should have selected for - if for whatever reason those cards aren't checked when trying to generate a Mythic from the pack that could explain this unintended behavior.
I'm assuming it's unintended behavior because the alternative is disgusting misleading and malicious behavior.
If it helps Draconic Destiny, Platoon Dispenser, and In the Trenches where the Mythics from Brothers War it should have selected for - if for whatever reason those cards aren't checked when trying to generate a Mythic from the pack that could explain this unintended behavior.
I'm assuming it's unintended behavior because the alternative is disgusting misleading and malicious behavior.