A small amount of metal in fine suspension is fairly normal in a new engine still breaking in. If the chunks were larger, it may be a concern. Did you take your
oil filter apart and check the filter material to see what was in there? Most of the metal particles should have been picked up by the filter, only the finest particles would get through or settle to the bottom of the pan (except for large pieces of metal that the
oil pump won't pick up.) I don't think I would worry about it, but keep an eye on things to see if it continues. It should be cleaner next time if all is well.
Bob