I guess it's possible Word 2016 has the option somewhere else. Here's a workaround:
• Press Alt-F11 to open up Word's VB Editor
• Paste the following line into the main window -
Sub SetDiacritics(): Options.UseDiffDiacColor = False: End Sub
• Press F5
• Press Alt-F11 to return to the document. Hopefully, your diacritics will now display normally.

Note: when you close the document, Word will warn about the presence of a macro. Ignore the warning and save normally, which will delete the above code but leave the updated settings intact.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]