After reading all the helpful and erudite comments, as a new member I am both impressed and thankful. I threw the stamp up on eBay on the hope that a collector with more knowledge than myself can make use of it.
Very interesting finding. Congratulations. I think is a mistake in the printing or over inked and the orange cover part of the letter"e". If is the only one known, has a very good value. This one deserve a certificate. Good luck and BRAVO.