Named entities present error. Sigil to Calibre.

I first edit the book in Sigil, run a error check in Sigil, no faults.
Open the same book in Calibre's Editor, Bug check returns "named entities present" errors.
Auto fix in Cal-Editor, ok. Bug check again, no faults.

If I re-open the same book in sigil and repeat the above I get the same errors Evident in Cal-Editor.

Why'm I getting these errors ?.

Below is the error snapshot.

Attached Thumbnails