Ink Pen problem

[samardac]

Hay, I see in User Manual this:

The ink pen is not affected by paper texture or canvas lighting.
It will not mix as you draw over other media, such as oils and watercolours, and they in turn will not affect the ink if you paint over the lines.

But in reality I can see texture and water collor affect ink pen stroke, check this screen, orange is ink pen an green is water color:



What is wrong?