[Elecraft] S meter interaction on K3

[Phil and Christina]

I noticed an odd thing today that I haven't come up with an explanation for
on my K3 (s/n 1826).  The S meter reading jumps about 4 S-units when I plug
in a headphone plug on the front panel.  It doesn't get louder (signal or
noise) that I can tell.  It just gives me an indication of an S8/S9 noise
level that doesn't sound like that.  Unplug the phones and it drops back to
about S3/S4.  Any ideas?  Thanks.

73,

Phil, NS7P