// Warning: Specified weight could not be set due to locked influences.
Then, if I go back to what I was painting, the Influence I added, no matter what value I had on the tool appears as completely white as a value of 1. As you might be able to imagine, this is incredibly problematic for animation purposes.
The only way I've found so far to fix this is to switch the Paint Weights tool from Interactive mode to Post mode. The error doesn't appear in Post mode, but the problem is now parts of the model can have simultaneous influence from different joints, whereas Interactive mode usually rectified this, and it does tend to cause issues later on.
Why is Interactive Mode not working properly? What can I do to fix it?