I now understand that 'this isn't a bug -- it's intentional': there is, by design, a discrepancy between WT and G2G profiles regarding which and how many badges are displayed.
So I am downgrading the title of this posting from a BUG REPORT to an IMP NOTE, and I will annotate the original posting to indicate that this is a design issue, not an implementation issue.
Why 'issue'? Because it violates the Principle of Least Surprise.