> Unless packet loss or increased RTT is seen on every hop between a given hop and the end of the trace, it is not a problem.

I once spent a month trying to argue this point to my ISP when they asked for mtr tests to diagnose a packet loss issue. My home router hop showed 90% ‘loss’ so they repeatedly refused to investigate on that basis.

The problem turned out to be widespread across their wholesaler’s network, but of course, according to the ISP, I was the only complaint they had heard of. Over the course of two years the wholesaler was bought out and their network upgraded, which immediately solved the recurring packet loss. Surprise, surprise.