I recently discovered that the TMG NLB fix provided in KB980674 should also applied to Forefront UAG array deployments that are configured to use integrated NLB.
At first glance, the KB article appears to be related to the use of NLB with site-to-site VPNs and also does not even mention Forefront UAG. However, if you read the KB carefully you will see this note:
Note The scope of this problem is actually larger than IPsec site-to-site VPN. The problem that is described here may occur in any array-based TMG 2010 deployments for which integrated NLB is enabled when NLB WMI events such as node convergence are triggered. Site-to-site VPN that has NLB enabled is the most visible example.
Therefore, any Forefront TMG deployment that is configured with integrated NLB will benefit from this fix.
Considering the fact that Forefront UAG installs and utilises Forefront TMG, this fix is therefore also necessary for Forefront UAG array deployments that are configured to use integrated NLB.
I am advised that the KB article will be updated accordingly.
Hope this helps…