[Elecraft] Anyone ever run across this quirk?

[Joseph Reed]

I have a K2 which has a strange quirk,  it has developed a "thump" when it switches from transmit to receive in cw when set for full QSK.  Very annoying, and when trying to DX at fast cw speeds, I can't tell what the DX op is sending.  However, if I change the T-R delay to .01 it doesn't appear.
 
This is a pretty stock K2 with KSB2, KNB2, KAF2, K60XV, KAT2 and K160RX.  Any ideas as to how I can get back to QSK?
 
Thanks,
Joe N9JR