[Plugin: WordPress SEO by Yoast] An invalid date was found. Please fix the date or formatting before

Google Webmaster tools is giving me an error in my Sitemaps. I know this has probably been addresed in the forums before but I could not find a post on it.

I am getting an error on my sitemap details. It is an: (invalid date error) and the Description is: (An invalid date was found. Please fix the date or formatting before resubmitting.) I am going to post the examples below, Please let me know if this is something I should fix I assume it needs to be fixed. Thanks CB

Parent tag: url
Tag: lastmod
Value: -0001-11-30T00:00:00+00:00
53
Oct 15, 2012
Parent tag: url
Tag: lastmod
Value: -0001-11-30T00:00:00+00:00
59
Oct 15, 2012
Parent tag: url
Tag: lastmod
Value: -0001-11-30T00:00:00+00:00
65
Oct 15, 2012

https://www.ads-software.com/extend/plugins/wordpress-seo/