I think it is the interaction of .URL being called by the template for the menu, and your URL settings in your config.toml.
Have a look at: Template menu generation .URL messed up using relativeURLs: true
I think it is the interaction of .URL being called by the template for the menu, and your URL settings in your config.toml.
Have a look at: Template menu generation .URL messed up using relativeURLs: true