If I had my best qualified guess, it's the combination of too highly set pickups (too close to the string) and - now a bit controversial and flame bit - playing technique.
I've encountered too many people who uses a rest finger stroke on all the rest of the strings, expect the lowest one. Since there's no adjacent string left to rest your finger at, on a 4 string E-string, or a 5 string B-string you TEND TO always start the attack of the string where you place the finger ON TOP OF THE string and move the finger downwards towards the pickup shell, so THE PICKUP SHELL STOPS THE MOVEMENT. You rest the string on the pickup instead. Which has some implications. Because people doesn't want the body to stop the motion, it is too far away.
This is mainly the reason why I've stopped loaning or borrowing out my bass guitar to people of shaky technique. At the end of their playing, they've always ripped up the pickup screws on the pickups bass end because they rest the fingers there with a force, and causes the spring under the pickup to move downards and then when the spring "jumps up" again, it rips the screw from its threads (actually the pickups gets pressed down first and then with its weight touches the head of the screw from underneath with greater force), and slowly erodes the wood, and all of a sudden the pickup is loose and can't be screwed back again, without having to refill the hole with a - say - toothpick and glue and then re-creating those threads. And when that pickup is loose, during playing, you bet that a huge clank or clonk is heard!
Maybe that is your problem? Check if the pickup moves by turning the bass upside down, pickups facing the floor!
That's why I am pretty sure a lot of people plays with a rest stroke there. But not rest strokes with the strings stopping it, but the actual pickup.
Bad conduct and bad technique. And of course, people won't move their picking/plucking area to a spot that is not exactly above any pickup because they want the timbre and tone from just that one sweet spot. I've solved this with silicion tubes instead of springs and metal thread inserts.
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FWIW I think it's bass player
Nathan Navarro, that has placed a special "dummy" pickup shell of wood, or something that makes him play with rest strokes, so a wooden plank underneath the strings stops the fingers from excess motion. It looks like and extra pickup but it isn't. Of course, the wood plank is placed under the sweet spot where he gets the best tone. He doesn't rest fingers ever on any pickup.
Check the background picture of this site (his YT channel)... However, the flip side to this must be that inhibits the funk, pop, and thumb and slap playing on the bass... at least in that area!
Nathan Navarro - YouTube