yeah, it concerns me too. The oil level is just short of the full mark and is fresh oil suggesting a recent change. The oil pressure light goes out when the engine is running so I don't think its the pressure. Not being as knowledgeable as some I have three suspicions at this point,
1. The pressure relief valve may be faulty
2. partly blocked breathers pushing crank pressure up into the engine forcing the oil down and partially starving the uppermost parts of the engine (I know, get them cleaned ASAP)
3. Sensor giving an incorrect reading. I read somewhere that there are sensors to detect oil lack and if the engine has been changed from one type to another where it doesn't have the sensor, it will produce this error. I can't say for certain if the engine has ever been changed but my thinking is that if a sensor malfunctions, it may have the same effect.
I'm probably barking up the wrong tree here and would welcome anyone's thoughts as you are all much more experienced than me in this kind of thing.
By the way, its an intermittent fault, don't know if that's relevent :-?