I had a similar reaction to the persona 3F. The high end in the measurements is consistent with my impressions.The Personas sound terrible. I briefly had a demo unit from a dealer and they made my ears bleed. They've been measured at the NRC Anechoic chamber. They sound exactly as they measure--bright and honky.
The Foundation series for all practical purposes is their flagship from an audio engineering standpoint these days, as the original owner bought the company back and designed this line to get the company back on track to their principles.
I think it helps to NOT toe them in, but that means you may have a "head in a vice" experience.
Side by side, KEFs and Legacy were much more natural sounding to me.