What's unclear that they may be mailed separately? It has nothing to do with activity in your account. SPG just noted that cards would be sent out in waves, based on status. US may be doing the same. Send out all the standard status cards in a mailing, then do a sweep of didn't-qualify-but-lifetime-Silver cards in a second wave a week or so later.

I'm in the same CP, dropped to nothing, but LT will keep me SLV, bucket. I've also heard nothing.