So sorry for not replying to this. I did see it on the day you posted and was going to reply later that day but... another senior moment and lapse of memory I'm afraid!

I do normally answer most posts the same day.
Well this is rather strange... the log clearly shows the 'roger' hotkey is used each time you hear your VCP confirming the frequency change, so I can only assuming something else is triggering that. Do you have that 'Enter' key configured elsewhere?
You say this only started happening after you changed the hotkey so my guess would be if you changed it to something else and ran a flight the issue would not occur.
Can't help much more than that I'm afraid because according to the log everything happened as it should.