Thanks.
We might be talking at slightly crossed purposes.
There is no problem unamplified. The problem occurs when the bass is amplified.
It sounds like a microphonic pickup to me (distorted echo and feedback) or does the famous rattle affect the amplified sound?
When I was talking about keeping the bass stock- I meant in respect a pickup change.
One possibility is that while you only notice it amplified, the tolerance could be such that it's there, but inaudible until you plug in. I didn't notice the rattle until I had about 100 hours on the bass. So, for me, it took some time to develop. Yours could be in a nascent state.
(I don't remember if I could hear it through the amp, or not. Once I heard it, I knew what it was and fixed it right away.)
I would give it try. It won't cost you much, if anything, other than time. BTW, you may have seen some warnings about removing the pickup cover. I didn't have trouble, but some have reported that the finish can attach itself to the cover and then get peeled off when the cover comes off. I was very careful to make sure that the cover came off easily with out lifting the finish.
Cheers!

