Gotcha. I actually checked my spells 2da before and the item ability for the Talisman is in my spells.2da but the label is wrong. At 99 is item_ability_energy_shield with the impact label k_sup_bands.
There are two instances of the Talisman ability in the spells 2da, both identical info aside from the labels (190 and 193).
I have posted my mod list, installlog and spells2da on the forum thread if any of that info is useful to you.