White border around sprite above videoPlayer

following tutorial here I made my VideoPlayer to be under the Canvas. I need some graphic elements to be over the video playing in the background.
Now I face a problem with Sprites which is over the VideoPlayer.

As you can see on the picture below, a white border appears when a sprite is above my videoPlayer. The part of the sprite which is not above the videoPlayer is drawn correctly.
The Premultiply alpha setting of the sprite texture is set to true.

Snímek obrazovky 2020-08-22 v 14.54.19

I use Cocos creator v2.1.3

Am I missing some needed settings? Is it possible to remove these white artifacts or not?
Thanks in advance!

Ok, I found out that this happens when the background colour of Camera is not set to black and transparent.
So this setting:
cc.Camera.main.backgroundColor = new cc.Color(0, 0, 0, 0);
fixed me the problem.

Unfortunately white border remained in case of sprites whith TYPE = FILLED, RADIAL (probably where cc.Mask is applied).