Automator Folder Action not starting

What does Finder -> select folder -> Control-Click -> Services -> Folder Actions Setup say about your existing folder action?

Are folder actions enabled in the setup window?

Is your folder action attached to your folder?

For diagnostics, create a very simple Automator folder action (such as "Ask for Confirmation"; it does not need to make sense, it just needs to be something that you can use to verify the folder action occurred), and attach that to any folder. If that works, build up to making your PDF action work.

For what it's worth, I had this problem too with a new folder action that scaled images. Started troubleshooting / googling and the folder action did its thing after a minute or so. Guess I just have to be patient with it.

I have setup 2 of these identical workflows on my desktop

Are they on the same folder or different folders?

but only one will run automatically.

which one works?

Folder actions cannot be assigned to a sub-folder of a target folder.