6475 IRS letter ( 3rd Stimulus letter. Tax Year 2021)

 Has anyone out there  received the 3rd stimulus letter ( 6475), but the other joint taxpayer has not received it yet?. There is supposed to be 2 letters sent out...each individually addressed and generally will come in the same mail drop.

 

Also, with the letter received, did the envelope itself say "IMPORTANT TAX INFORMATION ENCLOSED"?