This problem exist in LibO 3.4.4. and 3.4.3/ Step to reproduce. 1. Open Writer document. 2. Activate nonprinted character (View -> Nonprinted character) 3. Print document 4. Nonprinted character is invisible in screen now.
CONFIGURATION: Formatting aids - displayed nonprinting characters become unchecked during printing and PDF - Bug 40482 *** This bug has been marked as a duplicate of bug 40482 ***