6300 AGC on 50MHz

I have been using my 6300 a lot recently on 50MHz digital modes - especially JT6m and JTMSK, but also CW, and run successfully with my AGC turned off. However, I have noticed that whilst AGC appears to be off, the actual audio (using "remote") to my speakers seems to maintain an AGC profile (i.e. audio vanishes then slowly recovers) whilst the signal seen on the waterfall, etc. is - as expected - virtually flat response following a spike etc.   This all on SSDR 1.6.21. and using MSHV v1.15 and WSJT 10 r6088 or WSJT-X v1.6.1 r5910. 
Its not an issue for JT modes, but its not ideal for CW, as I can't hear the incoming signal until the AGC recovers. 
Anyone else notice this - or - am I not understanding what AGC Off implements / affects? 
73, Ian GM4KLN