Happens with my father and watches as well. The man cannot wear a watch without it dying within weeks. But thats another story. If you can isolate the symptoms to time of day or even the remote chance its a bad ballast (flouresent lighting used to cause occasional problems with old CRTs), etc. Atleast you can start to wittle things down a bit. But in this case it sounds like RF overlap. Perhaps there is one mouse that is emitting too strong a signal.
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