Did Serini build a mage breaker dungeon?

[Emanick]

You certainly need Trapfinding, but the spell gives that. More importantly though, we know that Haley hasn't been keeping her search skill max(x)ed, and she was still able to spot them twice - while rushing about in a panic rather than searching more methodically no less.

Personally, I suspect that the experience at Girard's pyramid prompted Haley to bring her Search ranks back up to maximum (after all, she would have known that they were headed to Kraagor's Tomb, which had been described like a classic dungeon, next). Rogues get enough skill points that they can do that rather quickly, and we know she's leveled since then.