B737 MAX 8 pilot reported a ramp employee showed the flight crew the exhaust plume metal had a large and visible crack; and mentioned that this was the second time noticing this issue. When the reporter later returned as a jumpseater on another aircraft; the same problem occurred again.

Narrative

While readying to close forward entry door; ramper motioned for my attention to take a look at the #1 engine. 737 MAX.FO and I went downstairs and saw the exhaust plume metal had a large and visible crack. Contacted Maintenance; wrote up and flight was delayed to next day. Ramper said he had found one a week or two ago - this was the second. It is above the tailpipe and would require crouching by the person doing the walkaround - the FO and I are unaware of guidance or training to inspect specifically this area.Due to long duty; I was released and was returning to ZZZ via jumpseat. When I arrived at jumpseat; Captain said the exact same situation had just occurred to him. His aircraft was now out of service until the next day.Cause: Inspection and review fleetwide. Was this just happenstance or is there something that we are not viewing correctly on walkarounds.If heat is allowed to penetrate crack into pylon; does this introduce the kind of risk that would be expected? Fuel; HYD; fire; structural mount failure?