I just tested it and everything worked on my system with the variables resolving and updating my CP as expected. I'll show you how i set it up and see if you did anything differently.
Here is my message:
Here is my action, using the alertmessage variable:
And here is the result in the Comment property that contains the message:
Strange... Same thing I did.
Are you NPM 12.0.1 or 12.1?
Wonder if something got fixed in new version.
That lab is 12.1 right now but I've used similar methods in the past and had the same results. Are you sure your variables are correct in the message itself? I've also seen some cases where newly created variables don't populate initially and a server reboot or configuration wizard sometimes clears that up.
Mix of old and new Custom Properties and yes they are correct as they populate properly when running a test simulation or execute as well as when a real event triggers the Alert Rule.
I ended up opening a SolarWinds case for this. What they discovered through analysis of a diag file was that I needed to "clear subscriptions". This process involved running a query against the SolarWindsOrion database which consisted of the following:
Delete From [dbo].[PendingNotifications]
Delete From [dbo].[SubscriptionTags]
Delete From [dbo].[Subscriptions]
Delete From [dbo].[ContainerMemberSnapshots]
Delete From [dbo].[LimitationSnapshots]
Once the execution of this query completed, I was able to see the new variables through the Alert Actions Insert Variable tool.
Thanks mesverrum for pointing out that my situation was not normal.