Much like you had to nerf Bone Dragon due to it bullying ranked PvP too much years ago. Any form of Bone Dragon over level 300 is ridiculously OP and should not exist as opponent. EVER!
Whether it’s World Events, Delves or Tower of Doom.
Unsurprisingly, it’s probably only OP because those events restrict players options to counter it. Resulting in a completely unbalanced game.
If your weapons are prejudice against Brown Mana potions “due to balance”. Then your designers should also be prejudice against Bone Dragons being an opponent in any event that restricts troop options.
Then again, Boned Rag(e) On(e)s is how you named the troop so perhaps the frustration is 100% intended.