Feed not validating

Hi Folks,

I guess this might be a simple thing but I am stumped. The feed from our site fails validation because of a “duplicate guid” error. This is pretty odd, because in fact the offending post does not exist at all. We have Permalinks set to https://www.cigarsense.com/2015/07/sample-post/. For some reason, in the feed I am seeing this URL show up twice:

https://www.cigarsense.com/2015/06/cigar-analysis-asylum-schizo-churchill-2/

In fact that’s not even a valid post URL – the correct URL is :

https://www.cigarsense.com/2015/06/cigar-analysis-asylum-schizo-churchill/

If you try the first URL you get 404. What I cannot understand is, given that’s not even a valid post URL, why is it showing up in our feed at all, much less showing up twice??

Any advice or insight is greatly appreciated!

Thanks to all the awesome WP volunteers who helps us newbs find our way…

DW