Selection highlight colors is indistinguishable

[nihlete]

For some reason, C/C++ language support create 2 types of highlight when user select substring of a symbol:

• Highlight of symbol
• Highlight of substring

What I've got with Dark+ (default dark) theme:

for me, it looks like proper behavior.

What I've got with Verdandi themes

On every picture, I select substring act in symbol action.

Interesting fact, that in an inactive window (for example when editor split in two) these colors are muted in different proportions, so highlights look like they should:

[VoronNess]

Could it be that some of the transplanted colors overlap or merge?
Took the colors from the file https://github.com/be5invis/vsc-theme-verdandi/blob/master/themes/verdandi-alter.json