Does anybody have an idea what can cause the startup rattle OTHER than oil filter leakdown? I do not believe this is always the cause. Although it does sound like a rod knock, it could be the timing chain. If there is a void in the oil supply, it does not have to be oil filter related. I believe that excessive bearing tolerance could cause the oil to drain into the pan from the crankshaft & rods.
Of course, a dealer will never admit there is a problem or offer any explanation.
BTW- I have tried several brands of filter & the noise is still sporadic.