This is an incredibly strange problem!
I too have my TI2 keyboard mounted on the second tier of my stand, supported by two arms, above a -- yup -- Nord Stage 2! Very strange indeed, as I suffer from the very occasional ghost note. (just this past weekend it scared the **** out of me - had a very loud patch set up in my Elektron A4, controlled via MIDI from the TI2, and after an hour or so of idle, out of nowhere comes the patch being played). Now of course one may suspect that it's the A4 that has the issue, but it never happens if the TI2 is off, and I've had other notes where I didn't have a pure midi patch (local off) dialed in to the TI2 also get played via ghost note.
Now, I am purely a studio hobbyist, not doing any of this in a gig environment or even for money, so I can live with the occasional glitch. But I find it very odd that merely tilting it level and putting the TI2 so that its rubber feet perfectly sit on top of the arms would fix the problem. FWIW, mine is not touching any metal, there are two very large rubber pads already mounted on the arms that it sits on, so I highly doubt there is any electrical short happening as a result.
Also, I've owned this TI2 kbd for less than a year. Had a TI2 desktop before it, and it too would throw the occasional ghost note.