CSS linespacing method produces inconsistent leading

[alerque]

I don't understand why yet, but the CSS linespacing mechanism has a monkey in the machinery that sometimes throws in a leading that's way too small.

Here is the MWE code:

\begin[papersize=a5]{document}
\nofolios
\script[src=packages/linespacing]
\set[parameter=linespacing.method, value=css]
\set[parameter=linespacing.css.line-height, value=14.5pt]
\font[family=Brill,size=12.8pt]
(Col. i) [The Athenians ?] considering [that to be not ?] only [impiety ?] but also the conspiracy of tyranny, (10) since they remembered the cruelty of the Peisistratids, pursued the perpetrators by offering great rewards for information. (15) Their principal suspect was Alkibiades, because they judged from his arrogance and high esteem that he was a man of great ambition. (22) A certain informant made no mention of the Herms but said that Alkibiades had performed the mysteries in Pulytion’s house. (28) So Alkibiades went to the Assembly, defended himself, and requested...
\end{document}

Switching to a different font, different content, or completely different metrics can easily throw this off. It wasn't obvious at first, but this does happen with other fonts, but not always the same way.

Using the same content as above but swapping out the font:

\set[parameter=linespacing.css.line-height, value=26.5pt]
\font[family=Crimson Pro,size=12.4pt]

Note with Crimson Pro it's pretty consistently the last line that is a problem (but not 100%) whereas with Brill it was pretty regularly the second to last line.