[Elecraft] K2 / KX3 receiver observation - need explanation

[gt-i at gmx.net]

Hello everybody,
during the WPX contest I noticed some weird sounds in the K2 when tuning 
to strong (>S9+20db) stations.
The sound was distorted, kind of ripple, but it did not sound like 
typical ringing.
I also noticed LZ9W booming in on 80m with S9+40db, producing 3 images 
in the K2 and the KX3. However, in the K2 the 2 ghost signals were 
frequency modulated. How could this happen?
Another big one, LY2W, also produced 3 signals in the KX3 but all the 3 
were nice and clean.

I thought these ghost images would depend on the receiver architecture, 
or am I wrong here?

Regarding the first observation: Since the K2 is already > 10 years old, 
could component aging already play a role. If so, where to look for?

Thanks for any ideas!
73
Gernot
DF5RF