How to spot Word 365 unintended changes during Protect a document "Start enforcement"

How to easily detect unintended change such as number of space between a Quick Part (Document Property; Subject) and normal text during process of  "Start enforcement"? 

I tried following w/o success:

1. set Quick-Part to color (other text are BW)  & print color as black and white. Disadvantage: requires Printer setting

2. Alt+F9: but Quick-Part code isn't shown

3. Word don't alert double spaces nor no space between abbreviated months e.g. JUL 2021

I am still relying on eye balling which is time consuming which is unexpected of Microsoft Office intelligence....