Just applied the latest hotfix and found that any RM 3.0 action that sets "string" based global variables needed to be re-done, most likely due to the new feature "Remove String". I can't say for sure if the action was actually broken by the change but the UI was all messed up so I assume so.
Just wanted to give you the heads up in case you can fix this before @AndyM applies the update and loses his mind!
The "set portion" was gone but the string value was still present. So I was able to fix by opening the "blank" action, choose set string and then the value appeared and allowed me to save. It also caused conditional actions that used string variables to have "blank" values until I opened and re-set them using the new UI.
I just created these rules this morning on 2.10.117. I only had two rules with about 10 actions between them so fixing it wasn't a major issue, but others may not have as much fun.
I've noted the problem in the hot fix release announcement. Will find a fix tomorrow. If you roll back they'd be fine. Or, as you found, just opening them and redoing them. I must have missed a step on the backwards compatibility. I know they still work correctly, it's just a UI issue.
So.....I just now got done updating hub 3......although I did get hit with a tornado while trying to update as to why I stopped responding......so you won.....lol