HI, I'm new here and was just poking around, and thought I'd interject.
I'm a long time guitar player, and I immediately discovered this same buzz issue when I started up on bass.
After some analyzing, I came to the conclusion that fret finger muting a note after it was played, which is completely legitimate and we don't even think about normally, but do it quite often, is a much different set of mechanics on the bass, compared to a guitar. I noticed I was lifting my fingers too lazily, created that buzz.
What worked for me on guitar, did not work for me on bass. I had to lift off faster.
IMO, it's essential to learn and know, the exact amount of pressure to fret a note, and the proper speed (quick) to un-fret that note. Ideally, fretting hand muting techniques should be combined with plucking hand muting techniques, in order to play cleaner and/or more controlled, if that is what is desired.