The only offering I can give, is that I have a similar problem but with a
cordless keyboard and mouse and have convinced myself that it is an RF
problem, don't know what though.
Try moving the sensor closer (get a USB extension but you should have one
anyway) then you can move the sensor around, just like I have done with mine
until I found a place where everything works all the time (stuck with
bluetack under the front of my desk, it doesn't get in the way and as I've
stated it works ALL the time)