When a new topic is created, the existing one is overwritten

In the Nested Spaces versions of XWiki, only one Topic can be created per Forum because the generated name is not unique (Topic) which means that the existing Topic will be overwritten by the new one.
Unique names could look like Topic_1892844838_23 where
1892844838 = timestamp
23 = random number
This way is almost imposible to have 2 topics created at the same time with same name.