I'm running vB 3.8.4, vBSEO 3.5.1 and vBET 3.3.4...
When I installed vBET 3.3.4, my "new" button stopped working and members are a little upset because they can't find the new posts in their subscribed threads. Instead of starting at the last unread post, it simply brings them to the first page in the thread.
When I disable the vBET plugin, functionality is restored.
I am using a custom string for the "new" posts: f[forum_id]/[thread_title]-[thread_id]-new/