Take a look at the non-printing formatting characters.

1. Ctrl+Shift+8 (Ctrl+*)
2. See Nonprinting Formatting Marks by Suzanne Barnhill, MVP
3. See also Basic Concepts of Microsoft Word - from Shauna Kelly

If you want, you can attach a sample file here with the problem and we can diagnose it more precisely.
Attach a Sample File Demonstrating the Problem - Here's How