Spacing with Font Roboto

[Alexander Krumeich]

Dear TL,

using the Roboto font results in strange spacing in the text layer of
the resulting PDF document. The page looks good on paper, but in the
text representation a space is added after some characters. Consider
the following MWE:

\listfiles
\documentclass[a4paper]{scrartcl}
\usepackage{fontspec}
\setmainfont{roboto}

\begin{document}
This is a test.
\end{document}

Following is a verbatim copy of the characters when I mark and copy
them from my PDF viewer:

T h is
is
a
te s t.

When I go back through older versions of my documents, I notice that
this behaviour was introduced sometime after May 9th. There's been a
change to the Roboto package in June. Possibly, something has been
broken with that update.

I'm using lualatex 1.10 on a freshly installed TeXLive. Listfiles
shows the files:
 *File List*
scrartcl.cls    2019/10/12 v3.27 KOMA-Script document class (article)
scrkbase.sty    2019/10/12 v3.27 KOMA-Script package (KOMA-Script-dependent bas
ics and keyval usage)
 scrbase.sty    2019/10/12 v3.27 KOMA-Script package (KOMA-Script-independent b
asics and keyval usage)
  keyval.sty    2014/10/28 v1.15 key=value parser (DPC)
scrlfile.sty    2019/10/12 v3.27 KOMA-Script package (loading files)
tocbasic.sty    2019/10/12 v3.27 KOMA-Script package (handling toc-files)
scrsize11pt.clo    2019/10/12 v3.27 KOMA-Script font size class option (11pt)
typearea.sty    2019/10/12 v3.27 KOMA-Script package (type area)
fontspec.sty    2019/10/19 v2.7d Font selection for XeLaTeX and LuaLaTeX
  xparse.sty    2019-10-11 L3 Experimental document command parser
   expl3.sty    2019-11-07 L3 programming layer (loader)
expl3-code.tex    2019-11-07 L3 programming layer
l3deprecation.def    2019-04-06 v L3 Deprecated functions
l3backend-pdfmode.def    2019-04-06 L3 backend support: PDF mode
fontspec-luatex.sty    2019/10/19 v2.7d Font selection for XeLaTeX and LuaLaTeX

 fontenc.sty
   tuenc.def    2018/08/11 v2.0j Standard LaTeX file
fontspec.cfg
 ***********

)
 430 words of node memory still in use:
   3 hlist, 1 vlist, 1 rule, 2 glue, 3 kern, 1 glyph, 5 attribute, 52 glue_spec
, 5 attribute_list, 1 write nodes
   avail lists: 2:21,3:3,4:1,5:24,6:1,7:29,9:10,11:3
</usr/local/texlive/2019/texmf-dist/fonts/opentype/google/roboto/Roboto-Regular
.otf>

Any hints? Thanks a lot!

   Alexander