The skipping gaps are the same size as the underline thickness. The underline thickness is configurable to be as thick as the author wants it to be. Therefore, if you have a short word with a single descender and a thick underline, the entire word could be skipped.
Perhaps the horizontal gap shouldn't be equal to stroke thickness, and should instead be proportional to font size.
Alternatively, we could detect when this occurs on a word, and just draw a solid underline for that word.
Created attachment 356245 [details] Screenshot