[Elecraft] LONG K3 birdie on 28.004.00 after new KAT500 Beta firmware upgrade?

[AC6JA at aol.com]

I used to have a short birdie on my K3 on 28.004.00 after keyup, but now  
after my 1.58 Beta firmware upgrade on my KAT500, the birdie lasts for 4 
seconds  after keyup.
Does anyone know how to get rid of this annoying birdie on 10 meters?
I  though somebody was keying up on top of me every time I switched to  
receive.
Any info would be appreciated.
Thanks.
 
Mike  AC6JA
 
K3 
MCU     4.83
FPF      1.15
DSP1    2.82
DSP2    2.82
 
KAT500
FW    1.58 Beta
 
KPA500
FW    1.37 Beta