I'm using Acrobat Pro DC under OS X. The Redact tool is doing something crazy: I select an item of text to black out using the Redact tool then select Apply. The tool blacks out the selected text but also deletes ALL of the other text on the page. That's not what I want.
Please let me know the exact dot version of Acrobat Pro DC installed on your Mac, make sure it is updated to the latest version Release Notes | Adobe Acrobat, Reader.
KB doc. for help : Removing sensitive content from PDFs in Adobe Acrobat DC
I checked for updates and it said that it is up to date.