[Elecraft] KX3 filters oscillating issue

[Terry Griffey]

I have a fully loaded KX3 with the roofing filter.  With the AF set to 12, the RF set to 0 and the monitor level at 19, when I start closing the filter (APF OFF) it begins to oscillate at bandwidth 1.8k until it gets down to .05k and stops.  This happens on every band. With (APF ON) the oscillation begins at 1.8k but changes timbre as the filter is closed to .05k but never stops.  This has been happening since I got the transceiver back from service a few months ago.  Is this a setting of some kind that got reset during service?  Is there something I need to change?  Thanks for your input. 73!

Terry - KG5OWB