We managed to find the culprit it's a unicode "backspace" character which has no graphical representation that goes into the translations.
What you can do to search the those invalid translations,
Go into the editor, on right side, open up the configuration panel, check on "Use syntax highlighting editor". All the red dot appears in the screen is the "backspace" character.
You can search for the character in the search field in editor and look for red dot using the syntax highlighting editor. You will need to copy and paste the char from character map with code U+0008