Oil Leak

I had a 45,000 mile check up two weeks ago. When I took off my front skid plates to prep for service, I noticed a good amount of oil leak. It was everywhere--on the skid plates, on my engine, you name it. I couldn't find the source of the leak so I had it steam cleaned (pictures below). One week later, I noticed it was coming from the front of the engine. When I brought it in again, they said the leak was coming from the timing cover. Luckily it was covered under warranty, but has anybody experienced a similar problem? It's currently in the shop and they said the engine or part of the engine will have to be removed in order to fix it. My poor FJ will be out of commission for the next 4-5 days. Is this just a rare occurrence or something common? I couldn't find much information in the blue room about it. What would cause something like this to happen?