Transmission Fluid in Oil-2000 Saab 9-5

I recently took my wife’s care into my mechanic because it had a serious knocking problem. My mechanic called and asked who did the oil change, because there is transmission fluid in the oil. He had seen it before with a quick lube place (just like we had taken it too). Would this have any effect on the motor if driven for quite a while this way?

I wonder if this is related to the toyota transmission failure post…