No longer shows hidden characters for one particular document.
I just updated to InDesign 14.0.2 x64 on Windows 7.
The option Type > Show Hidden Characters no longer works for this document.
It does not show newlines, paragraph marks, etc.
This document has one pages at 2.5" x 5" size, with only text.
Please confirm if toggling the View→Screen Mode from Preview to Normal, shows up the hidden characters
Bastian S. commented
Are you in the correct view mode? - press "w"