Date doubling up in Bibliography: Webpage reference

You need to look at the record holding the information and what fields contain the info you want to display in the output, and then look at the bibliography template for that reference type and the field and order they are displayed in – 

So which ref type (web I assume) and does it have a template in your chosen output style?  Sometimes not all ref types have a template, and it is using the “generic” option.