Is this a Recolor -Eraser tool bug? If it is, please don't fix it!

[Haoto]

I made a video on this here, play it at the linked timestamp where I explain and demonstrate : https://youtu.be/bh7DbbJPmdY?t=378
I explained poorly here but if you want me to make another separate video on this, I can do so.
 

Basically, what I did here is I manually used Eraser (Magic Wand tool doesn't work, this bug revolves around the Eraser & the Recolor tool) to render an image with vivid / expressive / complex background. One day, I wanted to press "E" for the Eraser but I instead pressed "R" on my keyboard, this is how I discovered the bug.
 

Here's an example of an image for you to compare :
[Original] : https://www.pixiv.net/en/artworks/81061252
[Edited] : https://twitter.com/Username_Haoto/status/1267355287809224709
[Extreme rendered example] : *In the video linked above
 

It usually works by creating those cool-looking artwork in black color ON the layer you rendered (any color choice works as long as it's not black for obvious reasons) and make sure that your cursor is applying the Recolor tool on the rendered/transparent area. I do it with a 2nd layer at the bottom of the main layer in any color to make rendering easier.
The results will always be different DEPENDING on how you render using the Eraser tool. It also doesn't work on already transparent images since it has not previous Eraser data in the history log.
If you want the linings to be in a different color, just use the Magic Wand tool with the right amount of tolerance, then fill in the desired color.
 

Maybe you can pull some artistic stuff off with another manually rendered image on the 2nd layer, but it's better if the software knows what the foreground (or the main subject) is so that it can pull of those cool-looking art accurately & appropriately (so that it wouldn't look out of place, I forgot the word).
 

Is this bug been here all long or is this the first time you've heard of this?
Btw, is this some kind of art movement? It looks really fascinating.

 

Edited June 12, 2020 by Haoto
MIssing info. Description bug.