hmmm, I am no expert by any means, but:
"Battle Lust is an item property found on certain weapons. A successful hit with such a weapon initiates a damage increase that is modified by several factors.
Significant damage received from opponents will be added to the attacker’s Battle Lust, causing them to do more damage to all opponents the attacker engages. This damage bonus is further modified by how many opponents the attacker is aggressed against.
The damage bonus is 15% per opponent, with a cap of 45% in PvP"
This does sound like battle lust damage would exeed the cap. But I cannot prove it of course.
I just thought this weapon should be usable mainly because of bleed stacking with splintering + infecting. Should be nice, I guess.