I encountered yesterday three Shadow Wyrmlings while walking stealthed in the Windy Canyon, and like all dragons, they've inherent True Seeing. However, in EfU the spell should not automatically reveal stealthed opponents and there doesn't even seem to be a bonus to Spot in the modified version. Therefore I find it odd that all three dragons spotted me as soon as I entered their line of sight. My character has a Hide/MS of 19/14 at the moment - not huge, but big enough that this left me wondering, especially since even against a godly Spot/Listen he shouldn't have been instantly revealed as the checks only happen once per round.

I've a vague recollection that merely changing the spell "True Seeing" doesn't necessarily change the permanent TS effect that some monsters have on them as part of their abilities, which may be the reason. If so, I'd like to see this changed, as it makes no sense if the actual spell still isn't able to instantly reveal stealthed creatures. In any case, I'm pretty sure that the above scenario was extremely unlikely if everything works as it should.

If you're aware of this and haven't planned on changing it, then consider this a suggestion instead of a bug report.

The base hide property called True Seeing is absalutely completely different than the spell script. On the same note, almost all monsters that have trueseeing in nwn have an ability called Blindsight or Tremorsense in PnP.

In Pnp Tremorsense (umberhulks) means they can know the location of enemies within a certain range who are in contact with the floor. Blindsight, a dragon ability is similar but detects any creature within range. In pnp the ranges of the abilities matter, in nwn, the screen may not be even a pinch into the abilities range.

Certain monsters (such as shadow wyrmlings and umber hulks, as well as grown up dragons) are fully intended to have true seeing as a natural ability. Quite different from the spell.