[Elecraft] K3 PSK filtering

[RICHARD SCHMIEDT]

I have a K3 S/N  abt 5000 which has both main and subreceivers with all recent mods including new synth boards. The filters are all 8 pole -- main configuration is 2.8, 1.8, 400, 250.  Sub receiver is 2.8 and 400.  All are correctly configured via the K3 utility and have given me no problems on CW, SSB and RTTY.  
However, on PSK31 I noticed last night that the IF BW only works in the 50 and 100 Hz positions where all seems well and the PSK is correctly decoded.  But at 150Hz, there is no signal at all, and above 150 the signals sound like they are outside the filter skirts. This is using just the main RX. 
I seem to remember PSK BW being seamlessly adjustable from 2.8 thru 50 Hz in my original K3 configuration, but many mods and firmware updates have come and gone.  Was something changed that I missed and  this is the way PSK should be working, or is something amiss??
Thanks all,RickW4GE