The o in “Notice” happens to start slightly to the left of a pixel boundary, so it has a narrow strip of very light pixels on its left side (pixels with maybe 10-20% coverage). That makes the boundary look fuzzier and rounder.

The o in “Today” is probably more or less flush with the pixel boundary, so its left side has dark-coloured pixels (80-90% coverage).

It’s likely also the case that it isn’t scaling the luminance to account for sRGB properly. If a pixel is say 20% covered by black-on-white text, you multiply 255 by 20% to give a linear brightness of 51; but for onscreen display this should be converted to sRGB, which is around 124 (gamma ~2.2). If you don’t correct the gamma, the left edge of that o is much darker than it should be, so it looks square rather than rounded off.

Opinions differ as to whether text should be gamma-corrected! If you don’t correct the gamma, it looks darker and sharper, which many people prefer. But it’s actually sharper because it’s more aliased, which exacerbates the kind of moire glitches you’re seeing.

I personally prefer text with no hinting and correct gamma, as I think macOS and iOS do it, but it does look much fuzzier on low-res screens that way so some people dislike it.