OK, upon inspecting this problem further, it turns out that it only seems to occur below a certain zoom level. When zooming in very closely, for instance to 800 %, the text appears to be displayed correctly.
Another thing I noticed is that, at lower zoom levels (even at 100 %), the weight of the glyphs is much too high, or in other words, the glyphs are too thick. While this problem also occurs when exporting the PDF without a blending mode for the text, it might still be related to the erroneous color rendering, because the more the weight of the glyphs normalizes when zooming in, the more the color of the text approaches the expected color.
OK, upon inspecting this problem further, it turns out that it only seems to occur below a certain zoom level. When zooming in very closely, for instance to 800 %, the text appears to be displayed correctly.
Another thing I noticed is that, at lower zoom levels (even at 100 %), the weight of the glyphs is much too high, or in other words, the glyphs are too thick. While this problem also occurs when exporting the PDF without a blending mode for the text, it might still be related to the erroneous color rendering, because the more the weight of the glyphs normalizes when zooming in, the more the color of the text approaches the expected color.