Weird that I used to have a Logitech G1 and I always put it directly in my dirty bag without any pouch, but it had never acted like this. This 1.1a, I always keep it in a mouse pouch after gaming but..
Does rapha even know about the cl_mouseacceloffset command? In his ugc config it was set to 5 and that is when his mouse problems started occuring. I think the default cl_mouseacceloffset was 5 but cl_mouseaccelffoffset didn't take effect until an update before ugc and cl_mouseacceloffset was set to 0 unless you had an old config with the old default value.