Mix brush behaving differently than it used to?

This post has been solved, please look at the next reply in this thread for the new problem

I’m having a problem since installing 2.80 official. The weight painting method I was using before is either broken, changed, or most likely, I’m an idiot and missed something.

These are my current weight painting settings;

If you care to see how this was working before, you can check this video here, I’ve linked it from the appropriate time;

Today however, the result is such that it’s painting a full weight of 1.000 on the vertex group I’ve masked and am painting over.

Before one click;

After one click;

I would have expected a weight of 0.050 to be painted, not 1.000
I’ve watched my own video twice now, and I’m not seeing anything that I’ve missed, so…what did I miss? :stuck_out_tongue:

OK, so I fixed that issue. Turns out, predictably, that I was the problem. I had the Bone_Root vertex group misnamed Bone.Root.

However I am observing the Mix brush not behaving as it used to behave. It used to work by adding to the group you were painting, while simultaneously subtracting from the Root_Bone (assuming auto-normalize is active) And successive clicks would add successive amounts.

Now it seems to be behaving as a replacement sort of brush. As in, if I add 0.300, it’ll add it once, but not twice if I click again. And if I change the value to 0.002, it’ll replace the 0.300 value with the 0.002 value, and return the leftovers back to the root bone.

Is there some new setting for the mix brush I need to change?