Sabre string crackle

I’ve noticed a problem with my beloved Classic Sabre. When I rum my fingers along the strings, I hear a soft crackling like static. The crackling disappears as soon as I touch the strings (or any metal part of the bass, such as the bridge or control plate) with my other hand. I’m uncertain as to the cause. Initially, I thought it might be a problem with the electrics in my house, except that none of my other basses behave like this. Could it be a shielding problem? I’ve e-mailed Customer Support, but they haven’t come up with anything so far.