[Elecraft] K2 XFIL Oddity

[Joe P]

I've noticed that as I switch between the different XFIL settings on my 
K2 (#3490), the pitch of the received signal seems to change sometimes. 
  The maximum change seems to be about 10Hz, small but clearly audible 
(and clearly visible on Spectrogram.)  On any given frequency, there 
will always be a pair of adjacent filter settings where the pitch shift 
is greatest, but the particular pair of settings will be different for 
different areas of a band.  For example, at the bottom end of 40m, it 
seems like the greatest change happens when switching from FL1 (1.5kHz) 
to FL2 (0.7kHz).  At the top end, it's when switching from FL4 (0.2kHz) 
to FL1 (1.5kHz).

It's really a minor thing but it seems a little odd. Is it normal?  Is 
there something I can do to improve the situation?

Thanks in advance.

73
Joe
KB8AP