Well at least the other Precise Strike page seems to go against current policy and has the correct information and not repeating the error from the in game description.
A choice for terminology NWN2 "This extra damage is not multiplied in the case of a critical hit." or d20pfsrd "This bonus damage is not multiplied on a critical hit."
Proposed description
Precise Strike
Class Prerequisite: Duelist level 5.
Specifics: At 5th level the duelist gains the ability to strike precisely with a light or one-handed piercing weapon, gaining 1d6 piercing damage. This bonus damage is not multiplied on a critical hit. Precise Strike is automatically in effect when the duelist has no off-hand weapon or shield. At 10th level the damage increases to 2d6.
Use: Automatic.
Notes
Although the in game description states "This only works against enemies vulnerable to critical hits" the feat is more similar to d20pfrsd and is only not multiplied on a critical hit. The bonus damage is also in effect when using a two handed spear.
D&D Note
This feat works quite differently than its D&D version.
NWN2 Tip
The bonus damage, may not always compensate the inability to use either a shield or a weapon in the off hand, however it can be effective with a spear.
Gameplay
A torch may be used in the off hand with this ability. Ragimund (talk) There's 2 separate pages for Precise Strike, so copied across both
Incoroprated some changes per your suggestions. Raelind (talk) 18:58, October 27, 2019 (UTC)