Dotfill after hypenation break

Question

It seems there is an issue with \dotfill after a hyphenation break, minimal example

\documentclass{article}
\begin{document}
hippopotamus, hippopotamus, hippopotamus, hippopotamus, hippopotamus
\dotfill 23 24 25
\end{document}

processed with pdflatex produces

Any ideas?

Note, this post replaces an earlier post which included details which I later found were not relevant to the problem.

Answer 1

TeX tries to avoid that line before the paragraph end has a hyphen. You can allow that by changing \finalhyphendemerits:

\documentclass{article}
\begin{document}
hippopotamus, hippopotamus, hippopotamus, hippopotamus, hippopotamus \dotfill 
23 24 25 

\finalhyphendemerits =0 hippopotamus, hippopotamus, hippopotamus, 
hippopotamus, hippopotamus \dotfill 23 24 25 

\end{document}