Neck pup twice as hot...

I have an Alleva Coppolo LG (jazz style) which has an active preamp.

This problem happens both in passive and active.

When both pups are on, it sounds fine. When you roll back to bridge, it sounds fine. When you have neck up and roll the bridge off, suddenly the neck pup output is about twice as hot.

The pup placement certainly isn't the issue, it sits pretty low.

Any ideas?

 

Update! The whole bass is actually quieter than it should be. I hadn't realized until I plugged a different bass in... the neck pup is closer to what a normal volume level should be. The rest of the bass, passive and active, is quieter than it should be.

 

That being said, the bridge and "both on" volume seem pretty consistent, close to correct.

The battery seems to have plenty of life, too.