It's often one of the bridge volume (or tone) lugs touching the copper shielding and thus grounding your signal when it's selective problem like this. Sometimes even a stray wire strand or solder blob can do it.
Just check that none of the pot lugs are brushing the shielding and/or the underside of the lug board isn't being squeezed down onto the copper (you can use some electrical tape to insulate the underside of the lugs if needed).
Last edited by WeirdBits; 22-10-2016 at 06:41 PM.
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