Opening a Style (Character or Paragraph) dialog's Font tab adds Asian text size (11) to the properties set in the style (visible on the Organizer tab). The Asian text font size is 10,5 pt by default. When the Fonts tab is opened, the fractional font size is wrongly detected as modified wrt initial; so the property is added to the style. It's impossible to remove this setting from the style afterwards.
https://gerrit.libreoffice.org/50066
Mike Kaganski committed a patch related to this issue. It has been pushed to "master": http://cgit.freedesktop.org/libreoffice/core/commit/?id=f00e891f3369f7b8c2532634d9ff4ab19da17c33 tdf#115892: properly get the box' saved value It will be available in 6.1.0. 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: http://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.