Sorry!
From the images, the piano looks close enough to damage the focus & purity of your system.
Having run across this issue dozens of times while voicing clients' systems to their rooms (and in each of these instances the piano needed to be damped acoustically), I thought that it might be slightly interfering with your sound.
There's a possibility it is effecting the sound but you may not be aware of it. I have a piano in my office along with my desk system and it's readily apparent the strings vibrate depending on frequency and amplitude. I also had multiple guitars in my 2 channel and eventually removed them because even after damping it was continually vibrating. Play a complex passage at a moderate or loud volume, listen near the strings and you'll know.