address book "when sending email" bug?

I see this behavior in outlook 2010, 2013, and 2016. maybe i'm missing something.

Address Book/Tools/Options, "when sending email" section.

outlook is using the order of the "custom" list, even when "Custom" is not checked.

so if i'm set up like the screenshot below, and I open a new email and type "john" in the To field, and hit ctrl+k to resolve the name (or just click send), I will only see "john" entries from SID Recipients, even though I have chosen to "Start with Global Address List," and the Custom list is greyed out.