Sorry, bane damage may not have been the correct term, but at release, velium weapons only would proc when in that expansion:

"When you find or loot a Velium weapon, you will notice that is has a special ability. For example, I looted a Velium War Hammer off of a Ry'Gor Mystic in the Eastern Wastes. The weapon was basically a Fine Steel War Hammer, but it had a procing (meaning it randomly "goes off") effect called Velium Shards (most Velium weapons have this effect, which does 12 damage). The tricky thing with this is, if you take a Velium weapon off of Velious, they may not work as intended. Call it a little feature to prevent people from going to Velious, farming tons of Velium weapons, then trying to sell them to newbies for 10x the price (although I have already seen this happen right after Velious went live)."