My understanding is that Diversive Tactics is supposed to grant the target 5% resistance (stacking?) to the damage type of the attack you hit them with, and a stack of vulnerability to all other types.

Is this currently working properly?

Trying it out last night, when I attack with a Warp Rod's primary attack (the LMB one) and my buddy uses Molten Beam, we see the words "Heat Resist" pop up in white.

Even when I'm the only one attacking, spamming the primary attack we don't see "Warp Resist", it's just more "Heat Resist". In spite of the fact that the primary attack doesn't actually do Heat.

Is something wrong with the display or the perk? It did actually seem to be reducing the damage he was dealing with Molten Beam, so we thought it might actually be applying Heat Resist.