Thanks for sharing I am having a struggle with my new MID 4003. Dull E string. Have swapped out the rick strings for tapered E Fender super Bass PLUS bought and fitted H*pSh*T brass bridege to try and save the original strings ... it's getting expensive
If your bass is a new one, it should have the new adjustible pole pieces. You will know if the button tops of the pole pieces have a hex pattern to accept the supplied hex key. if they are solid and domed, then you don't.
First, make sure the strings go directly over the center of the polepieces. If they don't then you might need to get a new set of bridge saddles and have them recut so the strings go directly over the polepieces. But, RIC QC (that's quality control, not "Queen's Counsel") is the standard by which all other guitar manufacturers aspire to, so I'm sure that is just fine.
First, raise the entire pickup on the bass side just slightly, like a half turn counter-clockwise, aka anti-clockwise (same direction, I just typed both words for both the British-English speaking audience and the American-English speaking audience).
If that doesn't work, assuming you have the adjustible polepieces, take the supplied hex key and turn it a half turn the same way.
If you go too far and get string clank, not to worry. Just back everything off a tad.