[Elecraft] K3 - HI CUR message

[Rick Stealey]

I suddenly am getting a HI CUR error message on 20 meters only.  I tested with 
a dummy load, all bands, and the problem is just on 20 m.  It happens when the
power is set to more than 60 watts.  Monitoring the current with the DISP I 
see approx 23 amps at 60 watts.
On other bands the current at this power is 15 amps.
Voltage is 13.9, dropping to 13.2.
PA temp is 34 degrees.
On ssb it is ok, until I whistle it up towards 100watts, then get the HI CUR message of course.
Any idea what might be causing this?

Rick  K2XT