That is indeed a feature, `WebHome` __is__ the name of the default document, but the URLFactory should not include it in the URL. The bug isn't that `Space.` is resolved to `Space.WebHome`, but that `Space.WebHome` generates a `.../Space/WebHome` URL, while `.../Space/` should work just as well. Look into the [`XWikiServletURLFactory`](https://github.com/xwiki/xwiki-platform/blob/master/xwiki-platform-core/xwiki-platform-oldcore/src/main/java/com/xpn/xwiki/web/XWikiServletURLFactory.java) for fixing the bug.

I think the problem is at [this line](https://github.com/xwiki/xwiki-platform/blob/master/xwiki-platform-core/xwiki-platform-oldcore/src/main/java/com/xpn/xwiki/web/XWikiServletURLFactory.java#L286).