Unwanted Glow Effect Appearing in Add Paint Mode

So while experimenting in verve tonight I came across a very undesired effect and am not sure why it keeps happening. Basically I would have paint buildup on 0% and if I tried to go to "add paint mode" an obnoxiously bright glow would be the only thing appearing. I attached images of before and after trying to add more paint so hopefully you can help! I should've just screen shotted it but I didn't think about it at the time and now the image is deleted due to me confusing the move canvas function with the resize function.

[Taron]

Welcome to the forum, first of all!
And now to your scary encounter with Verve features, hehehe. ...but you'll see that this is totally normal.
If you have 0% buildup, it will not add new material, but paint color on existing material.
If your paint mode is additive (+), it will literally add the chosen color value to the existing color on your material, leading to a glowing effect as you go beyond 100% (1.0) of the color values.
Additive refers to color brightness being added, meaning that, for example, if RED on the canvas is at 80% and you paint with RED at 50% on it, it will immediately result in RED at 130%, but it accumulates as you keep painting to RED at 180%, 230%, 280% and so on...

Also, if you really want it to glow, hehe, you can use the little GLOW dial above the color wheel. That's good fun!

There are three paint modes: ( = ) ( > ) ( + ) ...which is ABSOLUTE (=), ACCUMULATIVE (>) and ADDITIVE (+)
If you want to just "add" paint like in the "normal world", you do not need additive paint mode. For that you use the ACCUMULATIVE mode (>). This will keep accumulating material on the canvas as you paint, creating really thick paint layers as you keep going. The build-up amount determines the amount of material on your brush.
If you want to paint more photoshop like (or traditionally digital) you use the ABSOLUTE mode (=). In this case it will use the build-up amount as the absolute amount of material that will end up on the canvas. Confusing there can be the fact that it will ignore what's on the canvas already and bring it to the chosen build-up level, looking like it's cutting into the paint, when you go over existing paint.
If you want to make things glow or brighten paint, you use the ADDITIVE mode (+). This one will deal with material like the ACCUMULATIVE mode, but color values will be added, as explained above.

I hope that helps?!

Ahh that all makes sense now! Thank you very much Taron!!!