Well, I just captured smtp session of loopback interface (same box where
mutt is running). Here is the relevant part:
03d0: 746f 3e38 353c 2f74 6f3e 0d0a 0909 093c to>85</to>.....<
03e0: 7265 6164 3e21 d091 e288 9ae2 9591 3c2f read>!п.Б..Б..</
^^^^ ^^^^ ^^^^ ^^^^
03f0: 7265 6164 3e0d 0a09 0909 3c77 7269 7465 read>.....<write
As you can see, this character is already messed up before reaching
server. So, @gmail is not guilty here ;-).