Better hope that no teabagging was involved
On the grounds that the culprit was obviously a deviant one should be worried if any teabagging was involved in the adulteration of this classic drink. That white stuff may not have been just bovine lactate.
As for using a coffee pot for making tea, this should be grounds for instant dismissal. It may or may not change the quality of the tea but it sure as hell changes the flavour of the next coffee brew.