2012 rx350 rear cylinder head gasket leak

[JPMorno]

Hi! Anybody has an opinion on what to do with this report from my dealership? They found dried pink coolant on the side of the rear cylinder head gasket, not much they say, a small patch. My car never overheated, no warning sign ever, is running fine, the overflow was low but not empty, i've never noticed any leak on my driveway. It is a 2012 RX350 with 130000k (80000 miles), new suspension, new breaks, no rust, and totally paid. So my dilemma, do i keep it, because it was my intension to keep this car for many years to come, and be gentle with it? Or it is a no-no, it will fail soon and i should get rid of it? Thanks