UAG “Activation will start soon” stuck when joining a node to the array

This one terrorized me all day and just wouldn’t go away no matter what I did:

As it turns out, this is a symptom of having your nodes on different patch levels of UAG. The first node was SP1 with Update 1 while the second node only had SP1 applied. After applying Update 1 to the second node the array converged once I activated the configuration again.

I borrowed the following list from Ben Ari’s blog:

Here are some links that are related to these released:

• Download UAG SP1
• Information about UAG SP1 Rollup 1
• Download UAG SP1 Update 1
• Download TMG SP2
• Instructions for installing UAG SP1 Update 1 (this is important especially if you are installing on an Array!)
• Updated list of clients supported by UAG SP1 Update 1
• What’s new in UAG SP1 Update 1
• Release notes for UAG SP1 Update 1
• What’s new in TMG SP2
• Release notes for TMG SP2