Thanks for your help guys
“n00b alert” ...reset cvars?

I should have explained that this only happens occasionally (once every 2 or 3 hours) and is also very random. When I tried a clean install it still did it... no custom maps/mods etc. I also have Spearhead installed and it happens with that too. I now have numerous custom maps added to my main directory and if anything it seems to happen a little less than it used to.
I don’t get a flood of messages... although it seems to happen in the middle of, or after fire fights???