Something worth keeping an eye on.
In reviewing many post in Related Topics for an English site (OpenAI) starting to notice that topics in Spanish tend to be grouped together and suspect that if they were first translated to English each post would have a different vector and thus be clustered with other post. 
A side benefit of this feature for moderators is to check that the categories of the topics listed in Related Topics are correct.
As I review each new post I also check the Related Topics. This is becoming an effective way to identify topics created with the wrong category.
FYI - A related idea was noted in this feature request.
Find this topic when often needing following link which is not so easy to find so noting here.