Weight Paint Vertex Group Bug?

Hey team, have been battling with this problem for no less than a week now trying to solve it on my own but with no success so hopefully someone here can help me.

Basically its a problem with the weight painting in my different vertex groups randomly generating on their own.

I have my character rigged up and parented with my armature with automatic weights. The problem I’m having is that when I go through each bone adding or subtracting weights, other vertex groups that I’m not working on get randomly generated weights applied to them. I noticed it first when I went through each vertex group clearing all the weights so I could start with a blank canvas. Once I had finished with one vertex group I would move to the next, but then when I went back to a vertex group I had already cleared, it would have randomly generated weights on it. I can never have a 100% blue mesh. This makes weight painting impossible because when I work on one bone getting the weights perfect it’ll always do random crazy stuff in pose mode. I then go into the other vertex groups to find which ones are having an influence on that area as well and there’ll be a bunch that have just added a bunch of weight of their own accord. Every time I remove these and move to another vertex group to clean it up, the previous on I was just on will decide to add more random weights again. I’ve tried going through each vertex group getting the weight painting to how I want it, and then locking them with the padlock to the right of the vertex groups name so that they can’t generate their mystery weights while I work on the next one. This works well until I get to the end where I end up with two vertex groups. With these one’s, any time I remove a weight on one it’ll appear in the same place on the other. I have auto normalize on and X Mirror off. I can’t figure out if its a bug or me not knowing what I’m doing. I’m about to throw my computer out the window so any ideas would be appreciated.

Thanks in advance

It’s because you’re using autonormalize.

Let’s say you’re weighted 0.5 head, 0.5 neck on some vert. Half and half. You want to eliminate the head weights. As you reduce the head weights, the neck weights increase to maintain 1.0 total weights.

It might be a bug that locking doesn’t work on the last two groups, regardless of lock status, but you have to consider that you’re telling Blender to do the impossible: eliminate all weights from one bone, normalize all weights to 1.0 total, and not change any other weights. Something has to give.

Personally, I don’t use auto-normalize, so I’m not perfectly familiar with its details, but that’s what it does in general.