Created attachment 134524 [details]
A test document with runs with and without xml:space
Attached document has leading and trailing whitespace (tab and space) characters only in first line when opened in Word. Also, tabs between words also exist in first line. Second line has neither leading/trailing whitespace, nor tabs.
In LibreOffice, the two lines both have leading/trailing whitespace, and tabs between words.
The problem is absent handling of xml:space attribute (see paragraph 2.10 of XML 1.0 specification and 18.104.22.168 of ECMA-376-1:2016).
A patch is under review: https://gerrit.libreoffice.org/39682
Mike Kaganski committed a patch related to this issue.
It has been pushed to "master":
tdf#108995: take xml:space attribute into account
It will be available in 6.0.0.
The patch should be included in the daily builds available at
http://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More
information about daily builds can be found at:
Affected users are encouraged to test the fix and report feedback.