iPhone calls flagged as "Potential Spam" by Xfinity Mobile aren't being silenced as per settings

I know that for awhile Xfinity Mobile has had a feature where some suspected spam calls are flagged as "Potential Spam."  I would prefer that these go silently to voicemail instead of ringing the phone (iPhone SE Gen2, iOS 14.4), and was going to make that suggestion.

But I first checked settings, and apparently those calls *are* supposed to be silenced: Settings > Phone > Call Blocking > Silence Junk Callers (under "CARRIER CALL IDENTIFICATION") turned ON.  The description for the ON setting here says, "Calls identified by Xfinity Mobile as potential spam or fraud will be silenced, automatically sent to voicemail, and displayed on the Recents list."  Instead, as I said the "Potential Spam" calls are ringing until they eventually go to voicemail like any unanswered call.  So the feature apparently isn't working correctly, at least on my phone.  Any advice on how I might fix it so it actually works as the "Silence Junk Callers" setting describes?

FWIW, when I instead get calls labeled "Maybe: Junk" (maybe a Verizon network thing?), those calls *do* get silenced and go straight to voicemail.  So I don't have to be interrupted by them as I am with the "Potential Spam" calls.  But the "Maybe:Junk"  system doesn't seem to snagging many of my spam calls anymore; instead I'm getting more of the (unsilenced) "Potential Spam" calls.

Thanks.