Mechanic claims there was nothing to note - 3 months later I’m loaded with sludge. Does that sound possible? Please advise

I’d like an expert opinion - I purchased a vehicle sold to me with an aftermarket warranty applied at the dealership. Quickly noticed what I thought was sludge. Took vehicle in to the shop at the dealership that I bought it from. They said it was clean no issues to note. [I believe at this point they had a duty to acknowledge the sludge as it could have been treated, they refute there is no duty to do so] I didn’t get a second opinion at the time, I took their diagnosis of nothing out of the ordinary. However at that point - 3 months later my timing chain broke and because of a great load of sludge, the warranty is voided. I’d like to hear your opinion to their negligence. Would the sludge have possibly “hidden” from their inspection so that even if I saw it, it wasn’t there to view a few days later? Tell me how they can pay attention and say it was clean if 3 months later it was messed up and I have records of my oil changes in that time. Ideal Skills and Experience: - Extensive knowledge of GMC Terrain engine visual inspection and timing chain longevity - Experience in lasting performance of equipment in automotive - Problem-solving skills - Ability to provide strategic insights and practical consideration Looking forward to your bids!

Project ID: 39744603