MWE code
\documentclass[twoside=semi, a4paper, 11pt, open=any, chapterprefix=false, toc=graduated]{scrbook}
\usepackage{blindtext}
\usepackage{fontspec}
\usepackage{libertine} %uncomment
\usepackage[libertine]{newtxmath} %uncomment
\begin{document}
\chapter{Chapter One}
\blindtext[3]
\blindtext[1]
\section{Section One}
\blindtext[2]
\blindtext[3]
\chapter{Chapter Two}
\blindtext[4]
\blindtext[3]
\end{document}
Output -- unwanted spaces
Output -- desired effect
Question
How to fix this inconsistency in the same document? I noticed that by uncommenting the libertine lines of code the problem disappears.
Note
- compilation with XeLaTeX
This is XeTeX, Version 3.14159265-2.6-0.99991 (TeX Live 2014/W32TeX) (preloaded format=xelatex 2014.9.2)