Sometimes when you use an Action Set to execute and/or group some actions, it appears when part of the main flow.
It happens that when you have actions nested inside others, you'll have the possibility to mark them to run as the workflow owner only from the principal one.
Only actions at the root path of the workflow will have the Run as Workflow Owner option. If you have an action in any branch, this option will not be available.
I think adding some screenshots would really help this! Or are some there and not loading for me? It is a good fact to know, I saw that this was recently answered for
Maybe you could also let folks know why they might choose to do this? Just suggestions 
Nice suggestions Rhia.
I personally think also that this is a bug. I would expect that any action should have the same options available wherever it is within the workflow. I'll probably be creating a uservoice idea for it.
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