There are several reflections in your room that you should look into treating. The biggest one is sitting at 7.55 milliseconds in your ETC graph in both responses. Since it is reading on both sides, the issue is symmetrical. Check the ceiling, the floor, or front wall. It's not the exactly the same on the right, but it's very close. Could also be your side walls if the speakers are centered and the walls and treatment are mirrored/symmetrical. It's too close to be your back wall. The reflection around 3 milliseconds is also very similar on both sides. A desk reflection or something else close, like a coffee table maybe? The front wall? Symmetrical side walls?
At 5 milliseconds there is a reflection in the right channel that doesn't exist in the left. Check for something that is sitting on the left side of the listening area, or the right, that could be causing it. Could also be from asymmetrical walls or lopsided treatment. At 25 milliseconds there is another one, only in the right response. Since it is only present in the right speaker response, and it is later than 25 milliseconds, look first to the back left corner for this one.
See if you can track those reflection points down and treat them. Check your measurements to see if you can get them to disappear. They may be coming from places other than where I suggested, so do your best to hunt them down. Be sure to leave the mic in place while you do this.
