Display URL error and xml sitemap error

[multiuser]

Hello,

we have recently moved our vbulletin 4x, from a subfolder, to a subdomain:
example.com/forum --- > forum.example.com

We have 2 issues after the move:
1. Sitemap rebuild, doesnt work. It stays on processing status and never completes the build.
Note that the forum is in same dedicated server, so there is no different setup in server.

2. Google fetched the new urls yesterday, but I see in google all posts look like this:
forum/example.com/threads/21211
While it should show: forum/example.com/threads/21211-thread-title.
When I m inside the forum, it opens any thread with the correct - seo friendly url, like the one above.

There are no SEO Plugins installed in forum and also the whole process, was as as simple as taking a full backup of files and folders and moving them, to the new location.

I can not explain how there are issues, since there was no modifications and since server is the same one.

Lokking forward to any help,
Regards
N.