Definitely looks like the trays are not being loaded very carefully, that looks like contamination that got in with the paper and fed through the printer internals. Of course I'm just looking at pictures here, but it appears the service people came to the same conclusion.
The only way to make it a Warranty thing would be to show that whatever those things are, they came from something in the machine that broke, and that thing that broke would of course have to show no signs of being physically abused.
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