EM UI does not allow installing an extension on a subwiki when it's installed on another wiki

XEM after upgrade to 4.3 (4.1->4.3) upgrades only main Wiki as desired.
But it fails to upgrade sub-wikis.

When I'm trying to install UI XAR on a sub-wiki, it says me, that it is already installed on main wiki and gives no options to install it on the sub-wiki.

XWiki Enterprise - UI (% class

"extension-version %)4.3 ==

Installed
Back to list

by: XWiki Development Team

Default set of wiki pages containing both content and default applications for XWiki Enterprise.

Description
Dependencies

License: GNU Lesser General Public License 2.1
Website: extensions.xwiki.org?id=org.xwiki.enterprise:xwiki-enterprise-ui:::
Installed in the following wikis: xwiki

Main Wiki shows, that it is installed already on wiki farm.

XWiki Enterprise - UI All4.3

Installed

by: XWiki Development Team
All in one XWiki Enterprise XAR package

Description

License: GNU Lesser General Public License 2.1
Website: extensions.xwiki.org
Features: [org.xwiki.enterprise:xwiki-enterprise-ui, org.xwiki.platform:xwiki-platform-livetable-ui, org.xwiki.platform:xwiki-platform-index-ui, org.xwiki.platform:xwiki-platform-panels-ui, org.xwiki.platform:xwiki-platform-administration-ui, org.xwiki.platform:xwiki-platform-scheduler-ui, org.xwiki.platform:xwiki-platform-watchlist-ui, org.xwiki.platform:xwiki-platform-statistics-ui, org.xwiki.platform:xwiki-platform-search-ui, org.xwiki.platform:xwiki-platform-search-solr-ui, org.xwiki.platform:xwiki-platform-blog-ui, org.xwiki.platform:xwiki-platform-office-ui, org.xwiki.platform:xwiki-platform-webdav-ui, org.xwiki.platform:xwiki-platform-tag-ui, org.xwiki.platform:xwiki-platform-rendering-wikimacro-ui, org.xwiki.platform:xwiki-platform-annotation-ui, org.xwiki.platform:xwiki-platform-invitation-ui, org.xwiki.platform:xwiki-platform-extension-ui, org.xwiki.platform:xwiki-platform-sheet-ui, org.xwiki.platform:xwiki-platform-appwithinminutes-ui, org.xwiki.platform:xwiki-platform-linkchecker-ui, org.xwiki.platform:xwiki-platform-dashboard-ui, org.xwiki.platform:xwiki-platform-user-ui, org.xwiki.platform:xwiki-platform-logging-ui]

The only option I have is to "uninstall it from farm"

It was advised to import of http://maven.xwiki.org/releases/org/xwiki/platform/xwiki-platform-extension-ui/4.3/xwiki-platform-extension-ui-4.3.xar to fix a problem.

It fixes a problem, I can see UI as installed application, but with the only option to UNINSTALL it from XWiki farm. BUT it wasn't installed yet.