[Elecraft] K2 Choppy keying

[Bob G3PJT]

Hi
Just been playing with a K2 which was sent if for repair of the QRP PA.  
The K2 seems to have a funny keying characteristic. On cw the keying 
characteristic seems quite poor at high speeds. I notice too that if one 
rotates the receive "irt" knob while sending the keying goes horribly 
choppy.  Id be interested in any opinion.
Or are they all like this!?

73 Bob G3PJT