If the pickup is an under saddle piezo type at the bottom of the bridge slot, the saddle (the "bone part") needs to to sit firmly on the pickup element.
If the bone saddle fits too tightly in the slot, it may not sit deeply enough to make good contact with the pickup. The bottom of the saddle also needs to be straight, as do the bottom of the slot and therefore the surface of the pickup element. You need full contact along the entire length of the slot.
Ideally, the saddle should fit so that it can be pressed into the slot with only a small amount of force but cannot move around in the slot. You may have to sand the side or ends of the saddle to fit.
If you get the saddle fitting properly, and the G and E are still weak, try adding some shim material at each end of the slot under the saddle, a short strip at each end of the slot, none in the middle. Heavy Duty aluminum foil is about 0.001", and would be a good starting size.
Also inspect the inside of the slot for slivers of wood or ridges in the surface; anything that might interfere with seating.
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