Missing specific text
Designed in InDesign and exported to a PDF. I've downloaded all updates for both InDesign and Acrobat DC. I've tried to imbed the fonts using Preflight (this usually works but not this time) and have tried saving the file as an Optimized PDF. This instance is strange because it's only removing "fi" from the documuent (see the below screenshots).
PDF showing error:

What the PDF should look like without the error:

