I've noticed two big bugs so far with Spike Mail. When spike mail successfully prevents damage against a DoT type card (like an acid tile, burning damage, etc) it will pass the extra 2 damage on to yourself because it considers you the attacker(?) even though you are logically not. When a killing blow is dealt to your character, even if the spike mail roll was successful, the attacker does not take 2 damage.
It'd be nice to show logs, screenshots, etc. of this stuff happening. $:^ J Spiked Mail shouldn't hurt the attacker unless the damage was Melee -- meaning no Burning damage backfire. Also, Acid Terrain discards all Armor cards before they can prevent damage anyway. Now, a Melee killing blow -- as far as I'm concerned -- should still spike the attacker before the wearer dies, much like how (iirc) Elven Maneuvers and Martyr's Blessing will draw before one dies anyway. I'd say this is worth a test in order to present a log here if the bug is real. Regards, Bob $:^ J