Cut out overlap in Word and PDF

In the testing process I have discovered issues with my font when it’s used in Microsoft word or exported from Illustrator as a PDF. Some letters (but not others) seem to create a ‘cut out’ white effect where they overlap. Please see attachment for an example.
Is there as easy way to fix this issue?
font glitch.png

Run the font validator. Some of your glyphs have contours with incorrect direction.

Outer contours should be clockwise, while inner contours should be anti-clockwise.

Thank you very much! That’s fixed it. :smiley: