I am using
and validator (https://validator.w3.org/nu/) is throwing up errors about
"Internal encoding declaration utf-8 disagrees with the actual encoding of the document (windows-1252)"
So I went into server and changed from default of ISO-8859-1 to utf-8, and the validation error went away. However, a ton of sites where clients can type in their own content, probably cutting/pasting from Word, showed that weird symbol when there should be a hyphen or apostrophe etc. It is a black diamond with an s in the middle. So I changed it back because it would take me a zillion hours to track them all down and correct.
However, the first time I noticed the blank editor was before this weekend when I was testing out the validator. So I'll keep testing.
Where did you change to utf-8 in the test environment?