What is this character that keeps showing up in the Kindle online previewer? https://imgur.com/7lTDQAT
Daniel, I'm also getting this error!
I just updated my PubCoder software before starting a new project, and when I go to test-export it, I get the following error (see screenshot). Currently, it only has the cover page, and the metadata only. I tested two other files from previous projects which passed validation just fine at their time of creation, but are now getting this same error.
Did you ever get a resolution to the issue??