pixi-spine has unexpected results when color and alpha channels are split in Spine animation

[Friksel]

Since spine v4 makes it possible to split the color and alpha timelines I am using this for animating alpha only. However, pixi-spine doesn't seem to be able to handle this. It has all kinds of unexpected results. It looks like pixi-spine is not adjusted to the latest v4 pixi-spine related to this new feature of Spine.