Bar chart has border artifacts

## Expected Behavior
Bar chart with borderWidth = 0 has no border. The bar itself should be a solid block of the chosen color.
Bar chart with borderWidth > 0 should have a border in the chosen color, but no other lines/colors.

## Current Behavior
Bar chart has some kind of border, when borderWidth = 0:
https://codepen.io/nwi4/pen/KKvOdbW

Bar chart has some other lines around the border, with borderWidth > 0:
https://codepen.io/nwi4/pen/mdMNBJw

Are there some settings I am missing to tweak this behavior?

## Context
When stacking multiple (small) bars on each other, the unwanted lines blur the edges and it looks more like a gradient than multiple distinct bars:
There are 2 big bars, and 3 very small bars, which looks like the fade out of the bigger one before.

## Environment

* Chart.js version: 3.6.0
* Browser name and version: Chrome 96