We have a 2012 Accord v6 that had issues due to ECO a couple of years ago. As I’m sure you know, in ECO mode 3 cylinders (all on the same bank – the one closest to the firewall, if I remember correctly) stop firing, although they still go up and down, which creates suction that can cause oil to be pulled past the rings – according to our Service Tech at Honda. He said it only happens to a few engines – 1 out of 5000 was the stat he quoted me, but who really knows?
In any case, Honda fixed it for free with no hassle. They basically rebuild that half of the engine – new rings, head gasket, etc. I had purchased an extended warranty, but they said it was a known issue and did not mess with any filing of claims, etc. Had it back a couple of days later and it has run fine ever since.