I was able to replicate this in a Developer Org - below are the details:
Here's the Action:
The Action is simple - when used, the Opportunity's Stage is updated to "Closed Won." When looking at the Action's Layout, it works with or without (displayed below) fields present:
From Chatter, the Action looks like this:
From Salesforce1, it looks like this:
With the Chatter feed displayed at the top of the page, when you make an inline-edit, the Publisher Action will run:
- Before: The Stage is already set to "Prospecting" and the Approval picklist is blank
- Update: Using inline editing, the "Approval" field is updated to "Approved" and then the "Save" button is clicked.
- After: Once the page refreshes from the "Save," the Stage has been flipped to "Closed Won" as defined in the Publisher Action.
Again, this is in a brand new Developer Org where the only things created were the "Approval" picklist field and the Publisher Action. The above is not occurring due to any Apex Code behind or Workflow Rule Field Updates.
After pinging Salesforce, we've learned that this is a known issue with a patch due out soon. A possible workaround was to add another Action, a Create action for the same entity, if possible, and locate it to the right of the Update Action.
Other short-term solutions include hiding the Chatter feed when using inline editing mode or using the "Edit" mode and avoid using inline editing mode.