[Elecraft] [K3] 250hz 8 pole filter suddenly causes loss of signal strength

[kz5d at aol.com]

I spend 100% of my time operating CW and like narrow filter BW. Usually operate at 350 to 300hz BW, and often tighter, utilizing my 250hz filter. Today as I cranked down the Band Width, I discovered a 24 db drop in signal strength when the 250hz filter switched in. Went back and verified all the Config settings were correct. Filter is ON, Gn 4 db, Filter Frequency Zero (as per manual with 8 pole filters). 

Can the filter go South for no apparent reason? Or am I missing something. When I switch the filter in line, I basically lose a signal, dropping 4 S units.

The only other thing I've done is to align the Reference Oscillator with WWV after connecting a P3.

Your input will be appreciated.

73,

Art KZ5D