So I am working on an agreement template in Microsoft Office 365 Word. I have a plain text content control with Title and Tag "EffectiveDate". What I want is that whenever that content control is updated, that same content control is automatically updated wherever else it is in the document. I've half solved it by putting a bookmark on the content control and then having the other content controls cross-reference to that bookmark but the problem is, the update is not automatic. The file has to be refreshed for an update.

I tried using one of MS-Word's built-in document properties by going to Insert > Quick Parts > Document Property > Publish Date. I then go to Developer > Properties and updated Title and Tag to "EffectiveDate" but then when I try edit the placeholder text which says "Publish Date" by going to Developer > Design Mode, I keep getting the following error:

I get this error even if I just open Design Mode, make no edits to anything on the content control and immediately go to exit Design Mode.