[Elecraft] K3 - KPA500 power problems

[Gordon LaPoint]

I'm having a power out problem with the K3 when using the KPA500 and Writelog software 
for SO2V  (NOT SO2R) operation.   Normally when I put the KPA500 in operate the power out 
setting on the K3 drops to the normal 23-28 watts needed to drive the KPA500.  
Intermittently when changing VFO's and RX the power will come up at 100 watts and fault 
the KPA500.  If i put the KPA500 back in opeatate the next tx will work fine.
I have noticed this problem going from VFOA to VFOB (going to split) and the other way as 
well.  
What am I doing wrong?  It works most of the time!  Out of about 50 switches this 
weekend, only 4 overdrive faults on the amp.  (only ran 3 hours so only 90 contacts).

Writelog version 11.02A,   K3 SN:5651  MCU 4.39 FPF 1.14 DS1 2.73 DSP2 2.73, KPA500 FW 
1.11, P3 FW 1.12
Thanks!  
Gordon - N1MGO