Strange appearance of "&" characters as "&amp" in the HTML docs

At many (but not all) places in the generated HTML documentation, "&" characters are rendered as "&amp" instead of "&".

For instance, in doc/html/qt-gui-concepts.html there are places like this:

Device UI's & Qt Quick (OK)
Styles &amp Style Aware Widgets (NOT OK)

Those appear in the browser as:

Device UI's & Qt Quick (OK)
Styles &amp Style Aware Widgets (NOT OK)

I started a quick search in my Qt destination folder (as specified via "-prefix") for that isse:

egrep -lr '&amp[^;]' doc/

It produced the following result:

doc/html/best-practices.html
doc/html/hwacc-rendering.html
doc/html/style-reference.html
doc/html/qt.index
doc/html/qt.dcf
doc/html/qstyle.html
doc/html/model-view-programming.html
doc/html/qt.pageindex
doc/html/qtalgorithms.html
doc/html/overviews.html
doc/html/paintsystem-styling.html
doc/html/qt-gui-concepts.html

So at least those parts of the docs are affected.