The dip around 2.4kHz is a common feature among several speakers and a known tweak. It gives an enhanced sense of imaging. You can find it in several previous generation Wilsons, among others.
It is also a good crossover point between the tweeter and midrange, so it's relatively easy to make this dip happen in the crossover by spreading out the filter points a little more than you would use for a completely neutral speaker.
I doubt that’s from the room.
Personally I’m with Floyd Toole that EQ should be used sparingly and mostly in the bass, otherwise what is the point of picking out speakers you like the sound of?