I have several plants which are in pots & doing well. One although looking very healthy has pods which appear fine but are then going dry & brown at the tip & flowes inside are completely distorted. There appears to be a thick fungus on the inside of the pods as they grow. All plants have been regularly fed & watered in the same way. Leaves are strong & the stem is thick & sturdy.
Brugmansia pods do dry out as they mature, so that part is normal. Reportedly, the pods can turn slimy and disintegrate on the plant, dropping the seeds, and this is all normal (though it seems weird). I am really not sure what the fungus could be. This article lists fungal diseases of Brugmansia but none of these would be expected to attack the pod: