When some user edits any web content tool placed in Home, like Site Information Display, Home tool's property "Custom Title" changes to true.
This makes that the title of every Home tool (i.e. Synaptic Announcements, Messages & Forums, Calendar, etc) is saved with their current text and does not change anymore when user changes its language.
Just moving a line in the code to avoid this change when PortletIFrame edition is done inside Home would fix the issue:
Site site = SiteService.getSite(toolConfig.getSiteId());
SitePage page = site.getPage(toolConfig.getPageId());
// for web content tool, if it is a site page tool, and the only tool on the page, update the page title / popup.
if (toolConfig != null && ! SPECIAL_WORKSITE.equals(special) && ! SPECIAL_WORKSPACE.equals(special) )
// if this is the only tool on that page, update the page's title also
if ((page.getTools() != null) && (page.getTools().size() == 1))
String newPageTitle = request.getParameter(FORM_PAGE_TITLE);
More logic could be added, like changing Custom Title only if the title has been changed when saving.