Redaction tool leaving redaction marks and blanking out text

Adobe Acrobat DC

Version file: 2015.006.30280

Version:15.006.30280.16515

AGM Version:4.030.00067

Cool Type version: 5.014.00017

Core Version: 15.1536

JP2K Version: 1.002.00007.37658

Windows 7 64 bit

Redacted pages show up like the image.  Not every word on this page has been redacted yet the end result is only the redaction marks appear but the unredacted areas shown as blank space. The document appears normal until it renders the redaction. This only happens occasionally. The person then has to re-do the entire document again.

These are text documents only. I have found similar posts about this but never a solution, can someone shed some light on this?

This was happening in Version 10.1.16 previously as well.

Redact tool deletes all text on page. Am I doing something wrong?

https://forums.adobe.com/thread/2162157