Guernsey 1 double year bug.

It seems that in the year distribution of 1 Double Guernsey
https://en.numista.com/catalogue/pieces14768.html

instead of
1830 overdate variety on 1830 issue

there should be
1868 overdate variety on 1830 issue


As a result in Features section instead of
Country Guernsey
Years 1830-1911

there should be

Country Guernsey
Years 1868-1911

This variety is well known and described in many places, such as SCWC 7th ed. (2012) p.575