[Contra Fates]

Recently the big board I'm an Admin at has upgraded from VB3.8 to VB4.2 (current version), with some disastrous results. At first the issues were minor, but now we have a lot of strange bugs surfacing and little feedback from VB Support thus far. I figured it couldn't hurt to see if anyone here has had any experience with the following issues:

1.) E-Mail Notifications Won't Work.
For some reason, vBulletin's cron job that sends e-mails is actually blocking the outgoing e-mail relay. Whenever I unblock it, I can manually send emails directly from server shell until vBulletin blocks it again.

2.) Disappearing Posts & Threads.
We have threads that will vanish completely, as well as posts. They seem to still be present in the database, but not on the forum. I think it's an index problem, but the issue there is that rebuilding those indexes takes over 7 hours (the forum has over 7 million posts and 150,000+ threads), and any interruption could mess up the forum even further.

3.) Randomly Moderated Users & Posts.
Some new users are getting thrown into a Moderation Queue, despite no settings being enabled to allow this. Some posts are also randomly being thrown into Moderation when it's not enabled.

4.) Random Thread Subscriptions
Users have reported their Subscriptions being filled with threads they have not subscribed to.

Any suggestions would be very much recommended. The forum is huge, and the database alone is 15GB, so this creates some issues when it comes to trouble shooting. Thanks in advance!