Prevent knockout by using the Overprint options in the Attributes panel in InDesign.
Use of Overprint
What is a knock-out, trapping, and overprint in printing in terms of Adobe InDesign? - Quora
To Overprint or not to Overprint? Black is the Question! – Colecandoo!
print design - How to turn off overprint in Indesign? - Graphic
Overprinting in InDesign
The dreaded white box: How to identify overprint issues. - Eagle Web Press
Set a Swatch to Overprint
InDesign overprint
print design - How to turn off overprint in Indesign? - Graphic
Overprints, Knockouts and a hangover headache