Hello there, don't worry, I checked most of the threads including word "tailpiece" to find an answer but could not find an answer that satisfies my question.

So, I bought an epiphone century de luxe. It's all okay to this part. When I pluck a string, a sound comes from the tailpiece-bridge part of the guitar, you know the part with less strings. It sounds like harmonics or something like that. But when I put my hand softly between tailpiece and bridge, there's no unwanted sound that would normally come from there. I hope I was clear. Thank you.

Note: I've put on electric strings to test if it was related to type of strings I use, but no. Any kind of strings make that sound.