There is no bug in APT here. There is not even an error. It's a warning. In any case, this is synaptics fault, as that defines where to download the changelog instead of using APT's changelog code.
There is no bug in APT here. There is not even an error. It's a warning. In any case, this is synaptics fault, as that defines where to download the changelog instead of using APT's changelog code.